It depends on the purpose of the machine, but here are some of the apps I use a lot, which don't come pre-installed with my distro:
VLC, Samba, VirtualBox, TeamViewer, openssh-server, nmap, Fail2Ban, Remmina, Steam, NVidia driver (latest).

My preferred distro (Mint) already comes with most of the things one would expect for desktop productivity, including office apps, a PDF viewer, etc.

e16 and modified epplets
build-essential equivalent (depending on disto)
geany / geany-plugins
mutagen
lame
flac
exiftool
nano (if need be)
mpv
glances
mxrvt
HandBrake
pcmanfm
Eterm
MH5000
wmimagedock
cpufrequtil
various other little things as I remember them

1 members found this post helpful.

Bluefish first

Yakuake
Spotify
Vivaldi
SpiderOak ONE
ExpressVPN

Rather than adding things to a freshly installed linux system, I generally start by removing unnecessary cruft. For example if it's a wired host I remove Network Manager, because NM's really only worthwhile on laptops (on anything else it's just an annoying way to waste system resources and randomly disconnect yourself).

In installations that don't already load them, though, I'll install
vim
man pages
the GNU awk
nmap
bind
a mkhomedir system
policy monitoring/management utilities for SElinux if it's an SElinux distro
(and of course OpenSSH - but thankfully pretty much everything comes with OpenSSH preinstalled these days).

2 members found this post helpful.

VIM and VLC.

GPT

Thunderbird
Chromium browser
Kazam
Oracale virtualbox
nmap
hexchat
Terminator terminal
krusader
Handbrake
bluegriffon
vim

1 members found this post helpful.

I also do this on OS X:

• FISH
• neovim
• tmux (if it's not already there)
• Alacritty

System:

Clamtk
Firewall GUI
SSH server (not running by default in Mint)
rclone, wget, curl
latest nvidia drivers
Lynis - Linux server security audit

Utilities:

Bleachbit
Boot-Repair
Grub Customiser
Ubuntu system cleaner
Teamviewer
A lite PDF viewer/reader
pip / pip3
browsh (terminal web-browser)
ncdu, ranger, midnight commander (mc)
Parrot bash theme
A bulk file renamer - Used pyRenamer (old) trying Thunar Bulk Rename
Atom editor
Catfish (tfor ease of searching system)

Internet:

Firefox configured for privacy
Cheese
Tixati (torrents)
NZBGet (NZB file downloader)
Jami (testing alternatives for Skype - do not use!)
Filezilla
Bluefish

Media:
Plex
Kodi
VLC
A video editor (testing Cin, Flowblade, Olive, OpenShot and Shotcut)
Steam with Proton 3.16*
Handbrake

Privacy:
Tor Browser
Veracrypt
Cryptomator
Signal
NordVPN (configured through network connections)

1 members found this post helpful.

Chrome, Bleachbit, Aisleriot, makemkv, vlc

Usually I install the compiler and associated libraries for whatever language I'm currently working in. And a few games. Exactly what I install depends on what comes pre-installed, of course.

openssh-server and x11vnc so I can administer machine remotely.

generally go through and add those programs not installed with upgrades: nvidia drivers, then I go through to be sure things like skype, thunderbird mail, k3b, lucky backup, and a few others are automatically there, if not install them.

1st I install my printer. 2nd I install CrossOverOffice or Wine, and then install Quicken 2009. 3rd I install xscreensaver, variety, and rkhunter, and, depending on the distribution, and whether these are included in the distribution base, gparted, pluma, . Lastly, I install VirtualBox and copy my installation of Windows 10 machine into the appropriate folder, where it usually fires up and runs flawlessly. Things which I or others have written using MS Word sometimes do not translate well using LibreOffice. It's not worth the hassle to guess whether there will be problems or not. So, I make sure to use MS Word for everything that goes out to others, to insure compatibility.

No brag intended, but I can have a completely functional system for my needs in 4 hours or less, start to finish.

owa