First of all, the fact thaqt a creature has multiple printings does not mean that its more likely to show up in momir, f.e Giant Spider is as likely to be your 4-drop as Oracle of Mul daya. Therefore i will only focus on creature that hasnt seen print before. ( As i9m writing this, im actually unsure as to if Nightmare exists online before m14, ive never seen it in a Momir game)

7-drops: Fleshpulper Giant: Pretty unimpressive since his body isnt what you want, and he usually kills something irrelevant.

Groundshaker Sliver: Pretty Unimpressive

Guardian of the Ages: Hes not the card you want when youre ahead, but when youre behind hes better, still a 7/7 trampler on the ground is not that scary, so there is going to be a lot of games where opponent can trigger it without fear.

Windreader sphinx: There is a lot of fliers in Momir usually on both sides, so this guy might draw you some cards. he is also a pretty solid body. Carddrawing is pretty overrated in momir though, but he is still probably an above average 7-drop.

Colossal whale: One of the most punishing landwalkers ever, since a 5/5 is very fragile in combat if it can get blocked. Islandwalk makes it a Visara that deals 5 every turn. This guy is another reason to skip islands from turn 4 and forward (after missing out on Azorius Guildmage and the invasion-masters) if the defending players doesnt have Islands in play he or she must still be weary of keeping back enough blockers so that the whale can be killed even though the best blockers dissappear. ( F.e its enough to keep 2 6/6 creatures behind, but not a 6/& and a 4/4)

6-drops: We get a 4/6 vanilla, a 4/4 flier, a 4/4 basically vanilla (Stonehorne chanter) and a 3/4 red intimidator which downside is pretty irrelevant in Momir.

5-drops:  Now it starts to get interesting. Arcangel of Thune is the best card in the set for Momir. Not only is it very hard to race, it grows your team including itself. Opponent better have a flier with enough power to kill it, having a large toughness wont stop it from growing. And even then you get one anthemeffect out of it.

Shadowborn demon is interesting. he will put you ahead when you play him and you will then have the option to feed him every turn or sarcifice him to itself. Most likely the correct play will be to feed him since he does put you ahead when he comes into play and you usually have chaff to chuck to him. Don't be afraid to change plans with him if opponent hits a 6/6 flier or similiar.

Kalonian Hydra: He plays himself and can be unbeatable if he survives the first attack.

Woodborn behemoth: Solid but a 8/8 turn 8 might not even be the biggest dude on the board.

Thorncaster sliver: Pretty bad since he probably dies on first attack and he usually doesnt have sliver buddies to gang up with.

Sporemounder: Poor mans cloudgoat ranger.

Scourge of valkas: A firebreathing flier that pings when he enters battlefield is already pretty good. But even better is that its not that incredibly unlikely to hit more dragons in higgher drops.

Messenger drake: A nice flyer, but dont overreate the carddraw and throw him under the bus for no reason.

Vampire warlord: Not that bad since you often have gimps from your lower drops to toss to him.

Dawnstrike paladin: Pretty bad, hes basically a chumper that gains 2 later.

4-drops:

Seraph of the sword: Insane, not quite as insane as dawn elemental but almost as good. Attacks hard early, defends like a boss in the late game.

Lilianas revaer. Godd defense late and demands a block early. If u can force opp to chump this its pretty sweet, and opponent probably cannot allow this to hit you even one time.

We have 5 vanilla dudes, 4 of them with some advanced flavour text on them (Rumbling baloth, Ajanis chosen, bogbrew witch, elite arcanist, blightcaster)

Accursed spirit and charging griffin are good attackers early.

Maruading maulhorn are like all juggernaughts not long for this world, play them as aggressive as you can by maybe tossing some other dudes in combat to clear the way. Alternatively just let it suicide if u cant support an aggressive line.

Deathgaze cockatrice: Good offense early, great blocker late for dragons and angels and such. Dont trade it away recklessly.

3-drops: Banisher priest is ofc pretty sweet, other than that trained condor looks like it can steal some games.

2-drops: Imposing sovereign: Awesome if youre ahead, not that great if youre behind, u might want to trade it away then (Though it stops haste)

Manaweft sliver: Another manaproducer and therefore awesome. Vastwood hydra is a sad panda in momir though.

Conclusion:

Colossal whale is such an devastating creature when his landwalk ability is on that i probably wont play island after turn 4, also i might play 1 or 2 less islands in my deck from now on.

5-drops becomes slightly better with 3 really sick drops.

No drop in the entire format punishes you like Phage or leveler, although we get some stinkers they dont lose you the game.