This site has a comprehensive list of Unreal Tournament 99 console commands. Some necessary ones (for some you have to do adminlogin first, provided you’re playing on a dedicated server):

Restart mapadmin servertravel restart
Change mapadmin switchlevel (or servertravel) [map name]
Kick playeradmin kick [player]
Kick and ban playeradmin kickban [player name]
Remove all botsadmin killall Bot
Screenshotshot
Show player ip’sshowips
Show player id’sshowid
kick player with IDkickid [id]
kick and ban player with IDbanid [id]