Arctic, Avelon, Mlem.

My favorites for iOS are all Swift apps:

• Arctic: !arctic@lemmy.world (incredible smooth performance and feels like Apollo, pretty new app and still in TestFlight)
• Avelon: !avelon@lemm.ee (great features like gallery slideshow view inside posts for images and individual hide read posts settings)
• Mlem: !mlemapp@lemmy.ml (many customization options including unique ones like rearranging vote/save/… buttons in a widget style)