Board Game Oracle has a prime day page that makes it easier to browse through it and lets you filter further by BGG rank and other criteria.

Some small games that stand out to me:

• Jekyll vs Hyde $11.99 excellent 2P-only trick taking game
• Silver & Gold $6.49 fun flip & write by PWH
• Bruxelles 1897 $13.99 (not to be confused with 1893, this is a smaller card game)
• Pandemic: Fall of Rome $19.99 is my favorite Pandemic (along with Pandemic: The Cure)
• Horizons of Spirit Island $14.99 seems like a steal
• Glow* $23.49 is a cool drafting and dice placement game with neat art
• Coatl $20.99 is a set collection and drafting game with fun components
• Spicy $10.49 is a bluffing game that works at all player counts. Kinda like Liar’s Dice but with cards