GCD is used at run time in 320 crates (of which 48 optionally). It is a direct run-time dependency in 26 crates. It's used only as a dev dependency in 46 crates (of which 2 directly).

Depender (with downloads and own rev deps) GCD version
74K 117 fugit >=2.1, <3.0
33K 15 p3-poseidon2 ^2.3.0
11K 8 turbojpeg ^2.3.0
8.4K 4 rp235x-hal >=2.1, <3.0
1.5K 1 htb ^2.1.0
1.5K 1 rustscan ^2.0.1
800 7 ckb-std ^2.3
350 1 monument ^2.3.0
310 1 uu_dd ^2.3
150 prime_bag ^2.3.0
110 hesp-manifest ^2.3
4 const-frac ^2
p3-rescue ^2.3.0
floating_bar ^2.0.1
1 timestamp-stretcher ^2.0.1
quaru ^2.3.0
miter ^2.0.1
3 relp-num ^2.3.0
1 audio-engine ^2
miratope ^2.0
typus_fugit >=2.1, <3.0
1 klavier-core ^2
qalqulator ^2.1.0
numerous ^2.3.0
repetend_len ^2.3.0
ucsi ^2.3.0
1.5K 2 stable-hash dev ^2.1.0
250 hfs dev ^2.3