Simic is definitely hard-pressed for answers to
Supreme Verdict. You probably can't
protect your entire board, but you can diversify so that it doesn't completely stomp you.
Planeswalkers are powerful against Verdict: both
Garruk, Caller of Beasts and
Jace, Architect of Thought will help you
recover from getting your board wiped.
Jace, Memory Adept can beat Esper just by milling them out over the course of a few turns. Just back those guys up with counter-magic and you're good to go.
You could also try something like
Primeval Bounty, which forces them to use up their Verdicts and other removal much faster.
Mutavault is also strong, since you can attack with it without making it vulnerable to
Supreme Verdict. (
Simic Keyrune is another option similar to
Mutavault.)
Haunted Plate Mail has the same advantage, as well as winning the game faster on its own.
If you want to stick to traditional creatures,
Aetherling is the most resilient option.
Colossus of Akros will also survive a
Supreme Verdict, but at 8 mana it's very pricey.
If you can afford to commit to just one creature living, you could use
Mending Touch or
Trollhide, too. Or you could
Disperse or
Simic Charm one of your own creatures.
You might also find that creatures with the BESTOW mechanic - primarily
Boon Satyr and Thassa's Emissary - could work too (
Boon Satyr because it's big enough to win the game on its own; Thassa's Emissary because it will
restock your hand).
The other thing I can think of is to adjust your play style. Only commit at most 5 power to the board at once (outside of Thassa, if you're using her). Generally, try to get 3-4 power out there, then counter all their removal spells. If you convince your opponent that you're just going to keep countering until you can win with that 3-4 power, they might use their
Supreme Verdict prematurely (if they have one at all). If they do use it early, you've come out a little ahead, so you have a few more creatures left (in hand) than you would have otherwise.
Alternately, you could add White to the deck, giving you access to:
Rootborn DefensesReady // WillingElspeth, Sun's Champion
Voice of ResurgenceFleecemane LionIndestructibilityGift of ImmortalityAdvent of the WurmCouncil of the AbsoluteHeliod, God of the SunAlternately still, you could add Black to the deck, giving you access to:
Golgari CharmThoughtseizeDuressUnderworld ConnectionsRescue from the UnderworldWhip of Erebos