The Top 5 assumes Firefox, Thunderbird, and LibreOffice are included with distro.
1. KeePass2 (which I manually update to latest version not in repos)
2. Filezilla (because I maintain a couple of websites)
3. Wine (because of a couple of Windows programs I can't live without)
4. HomeBank (because it is FAR EASIER to use than GnuCash)
5. Vivaldi (and sometimes Chromium as spare browsers)
And beyond those above:
6. TeamViewer (because I am remote tech support for friends and family)
7. Zim (notes I want to save)
8. Gpredict (satellite tracking program)
9. Stellarium (astronomy program)
10. VirtualBox (for testing... something I do a lot)
11. DOSBox (for one REALLY OLD program that I still use)
12. Calibre (excellent e-book manager and reader)
A few others, if not included with distro: VLC, Xfburn, Brasero, Open Shot, Audacity, Gparted, Balena Etcher, AisleRiot Solitaire