solana-sysvar is used at run time in 272 crates (of which 19 optionally). It is a direct run-time dependency in 18 crates. It's used only as a dev dependency in 39 crates (of which 4 directly).

Depender (with downloads and own rev deps) solana-sysvar version
441K 78 spl-token-2022 ^2.2.1
346K 366 spl-token ^2.2.0
340K 601 solana-program ^2.2.1
142K 37 solana-program-runtime =2.2.1
134K 116 solana-account-decoder =2.2.1
127K 2 spl-elgamal-registry ^2.2.1
194K 44 solana-account optional ^2.2.1
41K 28 solana-stake-program =2.2.1
39K 22 solana-bpf-loader-program =2.2.1
39K 10 solana-system-program =2.2.1
17K 27 solana-cli-output =2.2.1
2.3K 4 litesvm ^2.2
1.6K 3 solana-cli =2.2.1
1.6K 6 mollusk-svm ^2.2
370 solana-hbase-writer =2.2.1
100 spherenet-program ^2.2.1
298K 5 spl-program-error dev ^2.2.1
128K 45 solana-message dev ^2.2.1
95K 3 solana-reserved-account-keys dev ^2.2.1
38K 5 solana-loader-v4-program dev =2.2.1
21K 10 solana-svm dev =2.2.1
600 12 agave-reserved-account-keys dev =2.2.1