solana-signer is used at run time in 318 crates (of which 26 optionally). It is a direct run-time dependency in 45 crates. It's used only as a dev dependency in 25 crates (of which 3 directly).

Depender (with downloads and own rev deps) solana-signer version
207K 8 solana-zk-token-sdk ^2.2.1
147K 45 solana-rpc-client-api =2.2.1
142K 11 solana-quic-client =2.2.1
142K 3 solana-thin-client =2.2.1
142K 14 solana-tpu-client =2.2.1
141K 30 solana-streamer =2.2.1
140K 269 solana-client =2.2.1
128K 40 solana-vote-program =2.2.1
125K 13 solana-zk-sdk ^2.2.1
104K 47 solana-clap-utils ^2.2.1
104K 26 solana-remote-wallet ^2.2.1
103K 52 solana-keypair ^2.2.1
312K 667 solana-sdk optional ^2.2.1
99K 5 solana-client-traits ^2.2.1
98K 4 solana-genesis-config ^2.2.1
96K 3 solana-offchain-message ^2.2.1
96K 5 solana-presigner ^2.2.1
96K 12 solana-system-transaction ^2.2.1
143K 26 solana-perf optional =2.2.1
105K 40 solana-transaction optional ^2.2.1
33K 11 solana-faucet =2.2.1
29K 5 solana-tls-utils ^2.2.1
16K 10 solana-clap-v3-utils =2.2.1
2.8K 4 litesvm ^2.2
1.3K 3 solana-cli =2.2.1
1.3K 1 solana-tps-client =2.2.1
950 solana-keygen =2.2.1
800 agave-install =2.2.1
750 agave-cargo-registry =2.2.1
240 litesvm-token ^2.2
120 litesvm-loader ^2.2
531K 80 spl-token-2022 dev ^2.2.1
168K 15 solana-config-program dev =2.2.1
146K 54 solana-rpc-client dev =2.2.1
142K 3 solana-rpc-client-nonce-utils dev =2.2.1
111K 7 solana-vote dev =2.2.1
102K 7 solana-ed25519-program dev ^2.2.1
101K 7 solana-secp256k1-program dev ^2.2.1
31K 5 solana-cost-model dev =2.2.1
22K 10 solana-svm dev =2.2.1
21K 12 solana-runtime-transaction dev =2.2.1
21K 3 agave-transaction-view dev ^2.2.1
16K 27 solana-cli-output dev =2.2.1
13K 6 solana-compute-budget-instruction dev =2.2.1
11K 19 solana-entry dev =2.2.1
9.2K 8 solana-poh dev =2.2.1
7.0K 1 solana-wen-restart dev =2.2.1
700 solana-tpu-client-next dev =2.2.1