In table format with FOSS status, platform, and OS for your (desktop) viewing pleasure:

FOSS Name Platform OS Stage Source Code Info
YES Memmy Lemmy Android, iOS Android Release (Pending Play Store Approval) Github memmy@lemmy.ml
YES Morpha Lemmy Android, iOS Under Development Gitlab morpha@vlemmy.net
YES Thunder Lemmy Android, iOS Alpha Release Github thunder_app@lemmy.world
YES Mlem Lemmy iOS Submitted for App Store Review (July 1) Github mlemapp@lemmy.ml
YES Jerboa Lemmy Android Released Github jerboa@lemmy.ml
YES Artemis Kbin, Lemmy Android, iOS Private Beta (Starts End of June) Unreleased ArtemisApp@kbin.social
YES Limbo Lemmy iOS TestFlight Beta Unreleased limbo@lemmy.world
YES Beyond Lemmy Android, iOS Under Development Unreleased original Beehaw post
NO Sync Lemmy Android Research N/A syncforlemmy@lemmy.world
YES Slide Lemmy Android Under Development (More information coming) N/A original Lemmy post
YES Lemmynade Lemmy Android Under Development N/A original Lemmy post
NO Connect Lemmy Android Released N/A lemmy community
NO Summit Lemmy Android Open Beta N/A lemmy.world
YES Unnamed Kbin Android, iOS Research N/A kbin post
TBD Lemon Lemmy iOS Development, Beta in Early July N/A lemm.ee
YES WefWef Kbin Web App Released Github lemmy.world

Important note from frasassi@kbin.social

Am super open to any apps, code repos, communities, or info I’m missing as well as updates.