Hello pandaeyedcat,
there is a selection of popular used software in Menu>System>Lite Software
In Synaptic if you left click x1 on one of the results in the package column, it gives you a description of it in the lower pane/window.
When you find one you like you right click and Mark for Installation, after you have finished marking one or more for installation, you click the Apply icon on the top of the Synaptic window.
To find additional ones there is a search bar to enter its name. Where I don't know a name initially I would type a keyword and read each result until I found the one I needed, some of the results I didn't read as in the far right column of its line there is a short description and this would help to see which ones were not what I wanted.
Another way as
@DeepThought wrote is to look online (there is a LL thread of this too), you could search for them later in Synaptic as you know there name. Not every software is available in Synaptic. Some require downloads, I found this the most difficult method when first installing things, as it requires more things that need to be learned of how to do this.
Another way is PPA, I've used some from here
https://www.noobslab.com/p/ppa.htmldo check its downloads section for compatibility first though
