This has been around for a long time and I’ve had it bookmarked for a while, but The Pinball Arcade now has an announcement that their license for Bally and Williams pinball games will expire at the end of June. So, if you’re interested in getting them, there’s just three weeks left. The ones I’m interested in are the three Pin-Bot games, Star Trek and Doctor Who, though the Black Rose pirate pinball game looks interesting.
Available on lots of different systems. The games are arranged by “seasons”, so you can’t pick just specific games to buy. Prices for the Steam versions are $30 or $40 for “Pro Packs”. If you need help identifying which games were made by Williams and Bally, use these two category pages from Wikipedia: