Open Source Password Generator
The strength of a generated password comes entirely from where the randomness comes from and where the generation runs - a pretty interface means nothing if the entropy is weak or the output passes through someone else's server on the way to you. The open source tools here generate locally with auditable randomness, so you can confirm the math yourself and know the only place a password ever exists is the machine that made it.
KeePassXC
Offline, encrypted password manager that stores your vault in a local KDBX file you control
KeePassDX
Lightweight, ad-free Android password manager for KeePass databases with biometric unlock and autofill
LessPass
Stateless password manager that recomputes your passwords from a master password, so there is no vault to sync
Padloc
Modern, end-to-end encrypted open source password manager for individuals and teams
gokey
Vaultless password manager in Go that derives passwords from a master password and realm string
xkcdpass
Flexible, scriptable passphrase generator inspired by XKCD 936
Readable Passphrase Generator
Passphrase generator that creates mostly grammatical but nonsensical phrases that are easy to remember
Pgen
Command-line passphrase generator with EFF wordlists, BIP39, entropy output, and dice mode
pwgen
Self-hosted password generator for passwords and passphrases with clipboard copy and offline mode