Edit: without any account!!!
https://github.com/fn2006/PollyMC - Fork of prism launcher to allow offline play without an account.
If I recall pollymc had a controversy about something that made everyone drop it for some reason, can't recall what it was though
The PolyMC controversy is that one of the devs went rogue and kicked everyone else off the project, so they didn't really have a choice but to fork. They explain what happened on the FAQ of their website.
Mineshafter[dot]info is what I used to use back in my cracked minecraft days. It basically provides a modified launcher that patches itself and the Minecraft JAR to look for the Mineshafter login servers instead of Microsoft's. It lets you use singleplayer as well as multi-player on cracked servers that do not force online authentication.
The site is still up and paid for, which means someone still gives a shit about it, so I think it may still be functional. I haven't used it in literally ten years though, so I doubt it supports the latest Minecraft versions though, but you can try it. Oh God. Ten years. I'm old...
