GCD is used at run time in 261 crates (of which 32 optionally). It is a direct run-time dependency in 24 crates. It's used only as a dev dependency in 41 crates (of which 2 directly).

Depender (with downloads and own rev deps) GCD version
60K 106 fugit >=2.1, <3.0
12K 14 p3-poseidon2 ^2.3.0
1.6K 1 htb ^2.1.0
1.2K 4 ckb-std ^2.3
1.1K 1 rustscan ^2.0.1
490 p3-rescue ^2.3.0
440 1 uu_dd ^2.3
350 1 monument ^2.3.0
110 hesp-manifest ^2.3
3 rp235x-hal >=2.1, <3.0
floating_bar ^2.0.1
quaru ^2.3.0
1 audio-engine ^2
4 const-frac ^2
miter ^2.0.1
1 klavier-core ^2.1.0
miratope ^2.0
3 relp-num ^2.3.0
prime_bag ^2.3.0
qalqulator ^2.1.0
1 timestamp-stretcher ^2.0.1
numerous ^2.3.0
repetend_len ^2.3.0
ucsi ^2.3.0
950 2 stable-hash dev ^2.1.0
250 hfs dev ^2.3