Btw. since I have setup WB 1.3 a few times, both because some games run better with the old OS, especially some of the early Gold Box games from SSI, but also because I have an Amiga CDTV setup where I have not installed a ROM switcher yet.
So I have looked into what can be done with WB 1.3 to enhance it in different ways. One thing worth looking into is JST an alternative to WHDLoad that works with WB 1.3, but it still benefits from having 2MB CHIP RAM and some FAST RAM as well.
With WB 1.3 its still best to load the games with a HD installation, and some games might not have its own HD installer but its still possible to make them run from a HD if you manually copy the files and put some files and some of them needs to go in libs folders and such.
There are apps with support for WB 1.3 as well. I can recommend looking through this thread:
https://eab.abime.net/showthread.php?t=52283
Some apps I can recommend:
Directory Opus DOpus 4.12 can also run on WB 1.3. This list mentions Directory Opus 4.37, not sure why but 4.12 is a version I remember as being the one to get, but I guess newer ones might also work.
REdit: A text editor I like to use. SysInfo 3.24 is nice for benchmarking, 4.x requires newer ROMs. My favorite painting / animation program is Deluxe Paint IV and it works in 1.3 as well. Otherwise all the archive utilities are probably worth adding, like zip, arj, LHA, LZ and so on and I think its worth looking into the different menu apps that can add popup menus and add custom menus to the WB 1.3 menu bar. There is also several icon utilities.
One special menu I will recommend is AmiDock. Its not the same as in AmigaOS 3.9, but its pretty nice for WB 1.3:
http://aminet.net/package/util/boot/AmiDock