Installing a new system - how to transfer settings and such from old OS?

I set a record of a 4 year install on my current OS (used to install 2-3x a year when I ran Windows and did tech support) - so YAAAA!

But being this was my first transition to Linux, I don’t remember nearly 5% of what I installed to make it run well. I’m running Kubuntu and I’d like to stick with that but and thinking of 16 or 18 LTS but had problems with 16 when I tried it years ago (networking and graphics were wonky and could’t get them to work right).

So I’m installing on a new hard drive so I’ll have the old OS to fall back on and transfer whatever from. Is there a way to find out all the packages I installed, software, and possibly settings? I had set up a lot of specific network shares and such (samba and other file sharing over the network) and lot of other config type files that I haven’t touched in 4 years.

Can anyone suggest a good process for moving forward here?