I wasn't planning on having an ongoing listing, but I decided to edit my list above to add the three games Tropicon mentioned that I added this past weekend.
Those are good choices. I'm sure I've said it's surprising that we haven't gotten maps of Final Fantasy VII yet. Other than the main overworld, I recall the game is made of prerendered areas, so it's certainly doable without even needing to fiddle with 3D stuff. PlayStation emulators have been reliable even when the PlayStation was still a current console, and there was a PC port (and I heard there is/will be a rerelease for whatever reason). For one of the most popular (and of course, overrated) games of all time, you'd think we'd have something from it by now. Similarly FF VIII also has prerendered areas (if I recall correctly) and a PC port (and no maps here yet).
I noticed Ultima and Final Fantasy do share a number of commonalities...
-both are long-running RPG series.
-IV is a popular one, and remade (well, many are, but IV particularly so). Ultima IV: Quest Of The Avatar is going to be rereleased as Ultima Forever: Quest For The Avatar and FF IV has been remade quite a number of times, including a DS one so soon after a GBA one.
-VI and VII of each seem to be the most popular in both series. VII even gets sequels. (Was Dirge Of Cereberus: FF VII any good?)
-VIII in both series seems to be a little less loved, and both have very unique magic systems compared to the rest of their series.
-IX gets back to their roots...back to Britannia in Ultima IX, and classic fantasy setting for FF IX.
-Ultima is split into thematic trilogies, Final Fantasy is split into trilogies by console generation (well, if they make Final Fantasy XV for the PS3, which might not happen as the PS4 is expected to come out this year).
-Ultima games' numbers are removed for a few of the console versions, Final Fantasy games' numbers are changed for a couple of the outside-of-Japan ones.
-both have a few rereleases and compilations.
-both have a number of spinoffs.
-both are pioneers in online MMOs.
Also, there is an "Ultima" spell in many Final Fantasy games and is usually the most powerful spell, or at least among the most powerful spells. Presumably from the same root as the word "ultimate", it's not necessarily a reference to the Ultima series, but someone might be about to mention it anyway.