Also, might i make a case for the skip regex being altered slightly? I would recommend it be changed to ((dis[ck]|tape|side|track)[ _-][b-l2-9])|(disc)[2-9]. The current one is ((dis[ck]|tape|side|track)[ _-]?[b-z2-9])
My reasoning is as such: in all my ROM sets, except for some Demos (which I had renamed, so that's on me!) i don't see anyone not putting some sort of spacer between "disk/track/side/tape" and the number/letter. There's a big ol or statement at the end there, and that's to account for the specific case of multi-disc gamecube games, which have a specific naming pattern that must be upheld. The "disk followed immediately by a number" can be the one except to the main rule that you need a spacer between disk/track/side/tape and the letternumber. But i see you asking, why the search space to b-l? So, there's a handful of games that are like "*side something". Side Pocket for Genesis, World Class Track Meet for NES.... and it seems like "m" seems to be the magic letter where you start losing games to be displayed. I ran a python script on my ROMs directories to see what titles were being caught up in the current skip-regex and what of those titles would be passed over under the new regex. What i found is that if i varied * [b-*2-9] pattern, from D to L, it excluded the same number of files from the regex matcher.If i went up to M, we lose things like "World Class Track Meet".
To prove my results, here is a list of files in my ROMs directory that were allowed to filter through the regex skipper if i were to implement it:
.\fbzx-Wii\snapshots\Inside Outing (1988)(Edge, The).z80
.\frodo\demos\67 Sidelined\Censor Design - Sidelined.d64
.\frodo\Games\Gunship\Gunship (1986)(Microprose Software)[cr L+T][One Side Version].d64
.\frodo\Games\Racing Destruction Set Custom Tracks\Racing Destruction Set Custom Tracks (1985)(Electronic Arts).d64
.\frodo\Games\Racing Destruction Set Custom Tracks - LaRock\Racing Destruction Set Custom Tracks - LaRock (1985)(Electronic Arts).d64
.\frodo\Games\Seaside Special\Seaside Special (1984)(Taskset)[cr ABC].d64
.\hatari\fd\Falcon Mission Disk Volume I v1.1 (1989)(Sphere Inc.)[cr Delight][one disk].zip
.\hatari\fd\Falcon Mission Disk Volume II v1.3 (1990)(Sphere Inc.)[!].zip
.\hatari\fd\Ghostbusters II (1991)(Activision)(Disk 1 of 2)[cr Empire][2 disks version].zip
.\hatari\fd\Goldrunner II (1988)(Microdeal)[cr Pompey Pirates][t][one disk][three data disks included].zip
.\hatari\fd\Iron Trackers (1988)(Microids)(FR).zip
.\hatari\fd\Kristal, The (1990)(Addictive)(Disk 1 of 2)[cr Pompey Pirates][2 Disks Version].zip
.\hatari\fd\SideWinder (1988)(Mastertronic)[cr Cruncher][one disk].zip
.\hatari\fd\SideWinder II (1989)(Mastertronic)[m].zip
.\hatari\fd\Tracksuit Manager (19xx)(-).zip
.\jzintvWii\roms\TRON Deadly Discs (USA, Europe).int
.\not64\roms\NBA Courtside2 featuring Kobe Bryant (USA).z64
.\ROMS\Amstrad CPC\Sideral War (Spain).zip
.\ROMS\fba\neogeo\ssideki.zip
.\ROMS\fba\neogeo\ssideki2.zip
.\ROMS\fba\neogeo\ssideki3.zip
.\ROMS\fba\neogeo\ssideki4.zip
.\ROMS\fds\Bomberman (Japan) (Disk Writer).zip
.\ROMS\fds\Clu Clu Land (Japan) (En) (Disk Writer).zip
.\ROMS\fds\Dirty Pair - Project Eden (Japan) (Rev 1) (Disk Writer).zip
.\ROMS\fds\Donkey Kong (Japan) (Disk Writer).zip
.\ROMS\fds\Donkey Kong Jr. (Japan) (Disk Writer).zip
.\ROMS\fds\Galaga (Japan) (Disk Writer).zip
.\ROMS\fds\Galaxian (Japan) (Disk Writer).zip
.\ROMS\fds\Xevious (Japan) (Disk Writer).zip
.\ROMS\GB\Bill Elliott's NASCAR Fast Tracks (USA).zip
.\ROMS\GB\Side Pocket (World).zip
.\ROMS\GBC\Resident Evil (Unknown) (Proto).zip
.\ROMS\GBC\Resident Evil Gaiden (USA).zip
.\ROMS\Genesis\Side Pocket (USA).zip
.\ROMS\MAME2003\coreE\trackfld.zip
.\ROMS\NES\Side Pocket # NES.zip
.\ROMS\NES\World Class Track Meet # NES.zip
.\ROMS\SNES\Mickey's Playtown Adventure - A Day of Discovery! (USA) (Proto).zip
.\ROMS\SNES\Side Pocket (USA).zip
.\ROMS\SNES\Tony Meola's Sidekicks Soccer (USA).zip
.\ROMS\wonderswan\WS-BW\Kiss Yori... - Seaside Serenade (Japan).zip
.\ROMS\wonderswan\WS-BW\Side Pocket for WonderSwan (Japan).zip
.\wii2600\roms\Tapeworm (USA).a26
.\wii2600\roms\TRON - Deadly Discs (USA).a26
.\wiiapple\Old Ironsides\Old Ironsides (1983)(Xerox Education).dsk
.\wiiapple\President Elect v2.0\President Elect v2.0 (1987)(SSI).dsk
.\wiiapple\Ringside Seat\Ringside Seat (1983)(SSI).dsk
Observe that i even had to rename the ROM to "NBA Courtside2" but that still did the trick.
The point being here that most people aren't using letters to identify their discs/disks/track/sides/tapes at a certain level. Maybe there are outlier examples i don't know about though.
Oh yes, this would have the added benefit of allowing games in directories called "tapes" or "disks" &c to show up, too. Which was a problem before i renamed said directories.