If anything can be considered a safe craft, here's a list of what's likely to be good over a few expansions: (epics and legendaries excluding quests only)
Zilliax has a lot of healing potential with magnetic. Make a big mech such as pogo-hopper and get 20 health after making a trade. Zilliax also trades nicely with many 4 drops so you can play it on turn 5 as well. On the other hand, siamat costs 7 mana, and does not have lifesteal. Giving him rush and divine shield to kill off a minion is a common play, but I wouldn't deem him necessary since he's slightly slow against aggro and doesn't help too much against control decks, unlike tirion fordring.
Corrupt the Waters: Safe craft, will definitely be playable not only now, but also at any point of time since the reward is pretty universally good.
Untapped Potential: Quest druid lacks early game tempo but cards like hidden oasis help recover a lot. Too many people are playing it so winrates might drop. Value overflows after you complete the quest (remember fandral staghelm?)
Bazaar Burglary: Quest rogue lacks early game tempo like quest druid, but the reward helps you beat control decks. Consider running more defensive cards (like khartut defender, zilliax etc) to make it all-rounded. 3/2 weapon with immune while attacking allows you to make good trades and conserve health. 2 mana for 6 damage over 2 turns is pretty good, and synergy with tess greymane makes thief rogue good against control.
Activate the Obelisk: Quest priest with the divine spirit/inner fire package is quite common now, and seems to fluorish in a mage and warrior-oriented meta. High priest amet is almost seen in every quest priest deck, so you might consider crafting him as well. Restoring 3 health and giving +3/+3 for 2 mana is actually pretty good against any type of deck. Quest may seem difficult to complete, but you will be able to do so sooner or later. Aggro decks will go face, and control decks will damage your minons.
Hack the System: The quest itself isn't too hard to complete, but the reward isn't that overwhelmingly strong. Compare it to quest warlock (un'goro) and you'll understand.
Zephrys the Great: Adapts to every situation, but can only be run in highlander decks. Safe craft if you plan to play wild highlander decks as well. Gives tirion every time if played right, gives ooze against a weapon, gives crazed chemist against doomsayer and kills jaraxxus with sacrificial pact. Gives you lethal with savage roar/bloodlust/damage spells. And it's not even random, it happens every time. Some run it in non-highlander decks for a late game surprise.
Anka, the Buried: Hasn't seen much play yet, most likely better in wild for combo shenanigans. Aside from being a little on the slow end, 1 mana 1/1 deathrattle minions work well with cards like necrium vial.
Octosari: Looks like a meme at first sight, and is most likely actually a meme. Aggro decks don't usually need a turn 8 play, and control decks don't need to draw 8 cards either. Also somewhat slow since it doesn't die quickly most of the time. But if miniature brawl ever comes back, you know what to do :)
King Phaoris: Used in mage decks with a lot of big spells, and meme paladin. Coin prismatic lens on turn 3, and hope king phaoris comes out as a 4 cost minion. All spell deck just for fun.
Psychopomp: Very solid card used in quest priest decks. Everything is a good target... except itself. The summoned minion (injured blademaster if you played it on turn 3) is usually pretty hard to remove on turn 4. Also really good synergy with high priest amet and activate the obelisk.
Plague of Death: Twisting nether but better. Removes any type of sticky board, and should generally be used in control priest archetypes due to high cost. Potentially a target for king phaoris along with mass resurrection
Tortollan Pilgrim: Often seen in highlander mage decks which already have a lot of value. Casting an extra copy of puzzle box of yogg-saron, blizzard, flamestrike or power of creation is usually a good idea seeing there's a 5/5 body attached. Be wary of having too many different spells in your deck since this card would end up being inconsistent, and hearthstone is all about consistency of pulling of combos and synergies.
Micro Mummy: Often seen in quest paladin, which specialises in beating control warrior. You might want to check out making mummies and da undatakah for that. Summoning a 2/2 copy of a minion with card text is good almost all of the time. This card could also see play in aggressive paladin decks, but since murloc paladin is dominating the meta, that has yet to be seen.
If anything can be considered a safe craft, here's a list of what's likely to be good over a few expansions: (epics and legendaries excluding quests only)
Anubisath defender
Tip the scales
High priest amet
Psychopomp
Plague of death (standard only)
Vessina
Diseased vulture
Armagedillo
Livewire lance (standard only)
Bloodsworn mercenary
Siamat (note that he's an elemental)
Zephrys the great
Vulpera scoundrel
Zilliax has a lot of healing potential with magnetic. Make a big mech such as pogo-hopper and get 20 health after making a trade. Zilliax also trades nicely with many 4 drops so you can play it on turn 5 as well. On the other hand, siamat costs 7 mana, and does not have lifesteal. Giving him rush and divine shield to kill off a minion is a common play, but I wouldn't deem him necessary since he's slightly slow against aggro and doesn't help too much against control decks, unlike tirion fordring.
Corrupt the Waters: Safe craft, will definitely be playable not only now, but also at any point of time since the reward is pretty universally good.
Untapped Potential: Quest druid lacks early game tempo but cards like hidden oasis help recover a lot. Too many people are playing it so winrates might drop. Value overflows after you complete the quest (remember fandral staghelm?)
Bazaar Burglary: Quest rogue lacks early game tempo like quest druid, but the reward helps you beat control decks. Consider running more defensive cards (like khartut defender, zilliax etc) to make it all-rounded. 3/2 weapon with immune while attacking allows you to make good trades and conserve health. 2 mana for 6 damage over 2 turns is pretty good, and synergy with tess greymane makes thief rogue good against control.
Activate the Obelisk: Quest priest with the divine spirit/inner fire package is quite common now, and seems to fluorish in a mage and warrior-oriented meta. High priest amet is almost seen in every quest priest deck, so you might consider crafting him as well. Restoring 3 health and giving +3/+3 for 2 mana is actually pretty good against any type of deck. Quest may seem difficult to complete, but you will be able to do so sooner or later. Aggro decks will go face, and control decks will damage your minons.
Hack the System: The quest itself isn't too hard to complete, but the reward isn't that overwhelmingly strong. Compare it to quest warlock (un'goro) and you'll understand.
Zephrys the Great: Adapts to every situation, but can only be run in highlander decks. Safe craft if you plan to play wild highlander decks as well. Gives tirion every time if played right, gives ooze against a weapon, gives crazed chemist against doomsayer and kills jaraxxus with sacrificial pact. Gives you lethal with savage roar/bloodlust/damage spells. And it's not even random, it happens every time. Some run it in non-highlander decks for a late game surprise.
Anka, the Buried: Hasn't seen much play yet, most likely better in wild for combo shenanigans. Aside from being a little on the slow end, 1 mana 1/1 deathrattle minions work well with cards like necrium vial.
Octosari: Looks like a meme at first sight, and is most likely actually a meme. Aggro decks don't usually need a turn 8 play, and control decks don't need to draw 8 cards either. Also somewhat slow since it doesn't die quickly most of the time. But if miniature brawl ever comes back, you know what to do :)
King Phaoris: Used in mage decks with a lot of big spells, and meme paladin. Coin prismatic lens on turn 3, and hope king phaoris comes out as a 4 cost minion. All spell deck just for fun.
Psychopomp: Very solid card used in quest priest decks. Everything is a good target... except itself. The summoned minion (injured blademaster if you played it on turn 3) is usually pretty hard to remove on turn 4. Also really good synergy with high priest amet and activate the obelisk.
Plague of Death: Twisting nether but better. Removes any type of sticky board, and should generally be used in control priest archetypes due to high cost. Potentially a target for king phaoris along with mass resurrection
Tortollan Pilgrim: Often seen in highlander mage decks which already have a lot of value. Casting an extra copy of puzzle box of yogg-saron, blizzard, flamestrike or power of creation is usually a good idea seeing there's a 5/5 body attached. Be wary of having too many different spells in your deck since this card would end up being inconsistent, and hearthstone is all about consistency of pulling of combos and synergies.
Micro Mummy: Often seen in quest paladin, which specialises in beating control warrior. You might want to check out making mummies and da undatakah for that. Summoning a 2/2 copy of a minion with card text is good almost all of the time. This card could also see play in aggressive paladin decks, but since murloc paladin is dominating the meta, that has yet to be seen.
Prioritise: Corrupt the Waters, Untapped Potential, Bazaar Burglary, Activate the Obelisk, Zephrys the Great, Psychopomp
Others have pretty specific uses, but it is generally recommended to hold onto your dust until the meta settles down in 2-3 weeks.