So let me get this straight what you're asking is that there should be another tab for Pokémon side games such as Pokémon Mystery Dungeon (PMD) and Pokémon Battle Revolution (PBR)?
When you say "tab" do you mean as in another tab along side the PokeBase, Meta and RMT tabs, or do you mean a tab at the top of the page next to the "Pokémon games" tab entitled "Pokémon side games"?
If the first case then this isn't really necessary since you can ask questions about games such as these in the PokeBase section of the site.
If the last case then this may be a good suggestion... but you'll have to rephrase your question so that it's easier to understand. Although the site mainly tends to focus on the main video games.
If you're asking for another tab for unofficial Pokémon games then this won't happen, as we only allow questions about official Pokémon games. Any Pokémon games listed here should be fine to post about in the PokeBase section of the site, since they are official Pokémon games and are developed by Game Freak and Creatures Inc. and published by Nintendo as part of the Pokémon media franchise.
Only questions about official Pokémon games are allowed. There are hundreds of different unofficial games that come and go all the time and have many varying rules; we can't cater to them all. Go and ask on their forums if you have a problem. Two exceptions are Pokémon Online and Pokémon Showdown which are popular battler simulators.
If you're asking for a tab for ROM or Emulator questions on the site, then this also won't happen as we don't cater for them as they are illegal.
If you are using a ROM and something weird happens (e.g. a Pokémon appears where it shouldn't) then it's almost certainly a glitch with the Emulator/ROM. Like above, if it's not an official game played on a real system, it's not our concern. Don't ask where to find ROMs, and don't link others to ROMs. They are illegal.
For future reference please look at the site's rule page. Thank you!