There are really goods suggestions in this thread, I just made a compilation of all the links posted (at this time):

Restfox https://restfox.dev/

bruno https://github.com/usebruno/bruno

Hoppscotch https://hoppscotch.io/

Hit https://hit.yolo42.com/

HTTP Client https://www.jetbrains.com/help/idea/http-client-in-product-c...

Hurl https://hurl.dev

Insomnia https://github.com/Kong/insomnia

Kreya https://kreya.app

Milkman https://github.com/warmuuh/milkman

Nap https://github.com/davesheldon/nap

Paw https://paw.cloud

restclient.el https://github.com/pashky/restclient.el

REST Client https://github.com/Huachao/vscode-restclient

Socketfox https://socketfox.dev

Step CI https://stepci.com

vim-http-client https://github.com/aquach/vim-http-client

vscode-restclient https://github.com/Huachao/vscode-restclient

verb https://github.com/federicotdn/verb