Draftsight: a multiplatform Autocad replacement
Draftsight is a good alternative for Autocad. Works on Windows, Linux an Mac.
Ranger is an interesting alternative to NerdTree on Vim. I’ve found it easier and more intuitive to navigate the directories and execute commands on them than nerdtree, but it lacks the possibility to show the working tree directly on the active buffer. It’s as well vim-motion-based and light weight.