Akkoma
Pleroma fork started in 2022 by a community frustrated with the Pleroma maintainer's politics and slow development pace. Actively developed, better moderation tools, defederation policies as standard.
Retains Pleroma's efficiency (Elixir, low resource footprint) + adds features: MRF policies (Message Rewrite Facility), better admin UI, Mastodon API extension. Defederation pre-configured against problem servers (Gab, Truth Social etc). Common choice for Mastodon-tired admins who want more control. Distinct from Misskey (Japanese fork tree, more anime features). FBA (Federation Bot Alpha) was the underlying inspiration source for the moderation stack.