Very useful thread, I am about to get my playfield back from clear coating and will be looking for more mods.

Don't forget about the LCD with video!
https://pinside.com/pinball/forum/topic/new-ish-tz-tv-mod-w-beautiful-video-playback

I recently searched out TZ mods and wrote down a wish list, I don't mind sharing that here:

slot machine kickout light: $30 (green)
http://www.leesparts.com/products/twilightzone-slotmachine-light.html

Pinball Decals TZ mod page
http://pinballdecals.com/PartsByGamePages/TZ_Page.html

Spiral Mod (much more expensive at Pinball Decals.com for some reason)
ebay.com link: itm

Ideas for mods/things to do here:
http://forum.arcadecontrols.com/index.php?topic=104171.0
color changing LED for ‘?’ and clock millions inserts
also plexiglass under mini playfield

Score cards: fit perfect with the theme. should probably get them professionally printed/laminated from kinkos or something.
https://groups.google.com/forum/?hl=en#!topic/rec.games.pinball/QuYFiLkMW5o

gumball led board:
http://www.iobium.com/installing_the_gumball_lamp_boar.htm

more ideas here: remove slop from auto-ball launcher
http://www.edcheung.com/album/album08/pinball/tz.htm

more mods: glass gumballs (higher end), new ROM
http://www.pinbits.com/index.php?main_page=index&cPath=13_2

more mods: lamp post?, thunderbird, camera
ebay.com link: pinballmodspinball

lots of cleaning and mod ideas:
http://tzpinball.tumblr.com/page/2
http://tzpinball.tumblr.com/page/1

more mod ideas:
https://pinside.com/pinball/forum/topic/fs-nice-twilight-zone-pinball-machine-with-2379-worth-of-upgrades-and-mods

More mod ideas:
https://groups.google.com/forum/#!topic/rec.games.pinball/gHygp2ndRi0

more mods, CHROME CLOCK HOUSING!!!:
http://home.myfairpoint.net/vze8f4tt/tomstwilightzonepinballmachineaccessories/id26.html

Ball diverter decal:
https://pinside.com/pinball/forum/topic/fs-twilight-zone-ball-diverter-decal-mod-get-yours-now

speaker panel lighting mod!
http://creditdotpinball.com/2014/07/20/mods-creech-speaker-panel-follow-up-and-installation/

Robby the Robot:
https://sites.google.com/site/detroitmichiganpinball/home/technicle-articles/twilight-zone-roby-robot-mod

Upper playfield switch replacements
https://ksarcade.net/tz-mps-kit-v2-twilight-zone-mini-playfield-switch-kit.html

felt strip, side rail tape, blue spring steel, gun blue
http://www.pinrestore.com/Supplies.html

Speaker kit
http://pinballpro.net/shop/williams-wpc-89-speaker-kit/

Wiring harness cleaner, purple power
http://www.walmart.com/ip/Aiken-Purple-Power-Degreaser-1gal/16778256

Slot machine coin box:
ebay.com link: Twilight Zone Pinball Machine Enhancement Cash Box With Buffalo Nickels Add On

Thanks for the link I do like those that you made up.

If you have any links to the directions on how to make any of the mods, that would be amazing! (such as the camera, slot machine, piano)

I have a mcdonalds piano i need to make into the mod when I get some time.

I just purchased one of these, also had an ebay coupon that brought it down a little more.
ebay.com link: Twilight Zone Flipper Super Slot MacHine Mod Add On

Thanks a lot for the links!

I had a 10% off 1 item coupon in my ebay account. single use. sounds like they give it out randomly