vim-signature

vim-signature (GitHub: kshenoy / vim-signature) by Kartik Shenoy can display marks and help navigate between them. This is similar to vim-showmarks, but removes the delay between setting and displaying marks, and adds navigate features inspired by mark-tools. It can also display multiple marks.

vim-foldsearch

vim-foldsearch (GitHub: embear / vim-foldsearch, License: GPL) by Markus Braun can fold lines based on a search pattern. This can be the word under the cursor, the last search pattern, a regular expression, or spelling errors.

The documentation includes suggested leader mappings, but the commands are easy to remember. Each command is two characters and starts with a F. For example, :Fp <pattern> will show lines matching <pattern>.