Disk Mimic! (shameless plug there.
Actually, ARP (AmigaDOS Replacement Project) 1.3 is at the top of my list. It provides full * wildcard support, and that is really something that I cannot live without. The ARP shell would be perfect, but it suffers from some show stopping bugs, so ARP 1.3 coupled with WShell 2.0 makes for the best 1.3 CLI environment.
HandyIcons from Fred Fish Disk 148 adds a menu to the Workbench that can be configured to launch programs. I've been using this from the very early days of the Amiga, and I can't imagine being without it.
Matt Dillon's DMouse 1.20 is a mouse accelerator and blanker, and it's definitely another must have.
And finally, Snap 1.4 allows you to copy and paste text from just about anywhere. It removes the need for a lot of tedious typing, and really speeds up doing things in the shell.