Plakar
French, EU-sovereign backup on the open ISC-licensed Kloset format: immutable, deduplicated, encrypted snapshots. Centralized fleet management and KMS are a paid Enterprise tier. A young project.
Backup & Recovery
Category: Backup & Recovery under Security & Privacy
Kopia
Encrypted, deduplicated backups to storage you own, with a built-in GUI and a multi-client server mode. You hold the keys, back up to S3, B2, Azure or local disk, every feature free.
Restic
Encrypted, deduplicated backups to storage you own, from one static binary. You hold the keys (zero-knowledge), back up to S3, B2, SFTP or local disk, and every feature is free.