Some lightweight tools I use frequently

[Muttley9]

Format Factory - Conversions between all sorts of media formats
http://www.pcfreetime.com/

Filezilla - FTP client
https://filezilla-project.org/download.php?type=client

7-zip - File Compression Utility
http://www.7-zip.org/

Tixati - torrent client
http://www.tixati.com/download/

f.lux - monitor brightness auto-adjust to time of day and room
https://justgetflux.com/

Medieval CUE Splitter - splits one track FLAC album to tracks
http://www.medieval.it/cuesplitter-pc/menu-id-71.html