solana-signer is used at run time in 360 crates (of which 30 optionally). It is a direct run-time dependency in 48 crates. It's used only as a dev dependency in 28 crates (of which 3 directly).

Depender (with downloads and own rev deps) solana-signer version
211K 8 solana-zk-token-sdk ^2.2.1
133K 47 solana-rpc-client-api =2.2.1
127K 3 solana-thin-client =2.2.1
127K 14 solana-tpu-client =2.2.1
126K 282 solana-client =2.2.1
126K 11 solana-quic-client =2.2.1
125K 28 solana-streamer =2.2.1
117K 13 solana-zk-sdk ^2.2.1
109K 38 solana-vote-program =2.2.1
105K 55 solana-keypair ^2.2.1
311K 665 solana-sdk optional ^2.2.1
101K 6 solana-client-traits ^2.2.1
101K 5 solana-genesis-config ^2.2.1
99K 4 solana-offchain-message ^2.2.1
99K 6 solana-presigner ^2.2.1
99K 13 solana-system-transaction ^2.2.1
81K 47 solana-clap-utils ^2.2.1
81K 29 solana-remote-wallet ^2.2.1
127K 24 solana-perf optional =2.2.1
39K 5 solana-tls-utils ^2.2.1
107K 45 solana-transaction optional ^2.2.1
32K 9 solana-faucet =2.2.1
14K 11 solana-clap-v3-utils =2.2.1
7.8K 5 litesvm ^2.2
700 3 solana-cli =2.2.1
700 1 solana-tps-client =2.2.1
650 solana-keygen =2.2.1
450 agave-install =2.2.1
370 agave-cargo-registry =2.2.1
290 1 surfpool-core ^2.2.1
170 2 litesvm-token ^2.2
litesvm-loader ^2.2
110 x1-sdk optional ^2.2.1
459K 83 spl-token-2022 dev ^2.2.1
153K 15 solana-config-program dev =2.2.1
132K 56 solana-rpc-client dev =2.2.1
126K 3 solana-rpc-client-nonce-utils dev =2.2.1
105K 8 solana-ed25519-program dev ^2.2.1
103K 8 solana-secp256k1-program dev ^2.2.1
88K 7 solana-vote dev =2.2.1
34K 5 solana-cost-model dev =2.2.1
28K 3 agave-transaction-view dev ^2.2.1
28K 9 solana-svm dev =2.2.1
27K 10 solana-runtime-transaction dev =2.2.1
20K 6 solana-compute-budget-instruction dev =2.2.1
18K 26 solana-cli-output dev =2.2.1
13K 18 solana-entry dev =2.2.1
11K 6 solana-poh dev =2.2.1
10K 1 solana-wen-restart dev =2.2.1
120 solana-accountgen dev ^2.2.1
solana-tpu-client-next dev =2.2.1