Game aids that have been useful to me
Over the years, there have been a variety of game aids that have been useful to me. Some of these have been supplements, others are more generic aids.
Battle Mat, Mega Mat, Crystal Mat. Berkely Games was the first distributor of vinyl mats printed with square or hexagonal patterns, other producers have produced similar products. The Crystal Mat is especially nice being a clear sheet of vinyl that can turn any map into a hex map (when I started playing D20, I wished these were still available so I could get one with a square grid).
GURPS Battle Maps - this product, released early in the life of GURPS was a set of three 21"x32" double sided hex maps. One side was printed in black and represented a dungeon or town. The other side was printed in brown and green and represented wilderness. I used the wilderness side of these all through one Cold Iron campaign (to the point that the players knew the best place to set up camp on each map, and used the rocks to great advantage).
Page protectors - these are absolutely a must for use with Rune Quest character sheets, allowing marking off individual hit point and power boxes, and then wiping the marks away as hit points or power are recovered. In other games, these are useful to protect heavily used pages of charts.
Judge's Guild's First Fantasy Campaign - this is a nice little campaign setting, documenting Dave Arneson's Blackmoor campaign. There's not a lot of detail in the book, but the map is gorgeous. There are several interesting places noted on the map. In the 1980s, TSR reproduced the map in color for their Blackmoor series of D&D modules. The last module added an extension to show the Valley of the Ancients (JG originally slightly modified the map so it would fit into their Wilderlands of High Fantasy setting, though the map scale was 10 mile hexes instead of the Wilderlands 5 mile hexes). This campaign setting has been re-published by Zeitgist Games in conjunction with Goodman Games, though with a new map (that isn't included in the book - I snagged a couple copies from their table at Gen Con though).
Judge's Guild's Wilderlands of High Fantasy setting - this was a really nice campaign setting. The maps still are my standard of reference for campaign maps. The only product released since that I consider serious competition is Harn. Most of the maps have little patches of different terrain scattered in (most campaign maps have huge swaths of one terrain, some even have each country basically be a single terrain). Roads, villages, and keeps are marked all over the map. This campaign setting has be re-released by Necromancer Games (the new maps are not quite as nice, but a lot of detail has been added).
Lou Zocci's 8-sided d4s. The d4 "caltrop" never rolled very well. Lou Zocci produced an eight sided die with blunted points and in funny colors marked 1-4 twice. These are the only thing I ever use for d4s.
Dungeon Magazine (especially pre-D20) - I was still playing D&D when Dungeon Magazine was first announced and I quickly subscribed. Soon after, I stopped playing D&D, but every issue seemed to have at least one adventure that was easy to translate into other games. I have used Dungeon Magazine adventures in Rune Quest, Cold Iron, and Arcana Unearthed/Evolved. Lately, I don't find it as useful since the adventures tend to be larger, and the color maps while looking pretty somehow don't inspire me as much as the simpler line drawings of the early days (which could also be photocopied so you didn't have to keep flipping pages as much). Still, this is the only magazine to which I've never let my subscription lapse.
Borland Sidekick - it's been a long time since I've made regular use of a computer at the game table, but I ran an extended Traveler campaign bringing my Compaq suitcase computer to game sessions. I would run Sidekick in the background and keep all the game notes in the notepad. In the foreground, I would run a variety of programs (especially a program I wrote to manage fuel costs for jumps using a fine grained system of my own). My use of this computer sold at least two people Compaq systems for their own games. In these days of laptops, I somehow seem to find the computer a distraction during play, though I use the computer heavily during prep.
D&D Miniatures game - The easy availability of pre-painted miniatures is a blessing. One bummer though is their 28mm size compared to the 25mm that was popular in the 70s and 80s. I have lots of lead miniatures that are nicely painted that get looked over by the players because they're too small (and some don't stand up well - the consistent round base size of the D&D minis is nice - and it's a shade smaller than 1" so they fit well in close formation on 25mm and 1" battle mats). It's still a pain to try and have figures for all the monsters though, and every game I run seems to have a PC race or two that just aren't available, or at least not in enough quantity.