Short answer — there’s no single official source that searches every program, but a handful of specialist tools + program/partner sites let you compare award availability across many loyalty programs:

Recommended tools and what they do

• Point.me — searches many airline programs and returns award-booking options across partners (paid; good for wide comparisons). (nerdwallet.com)
• ExpertFlyer — powerful for searching award/upgrade inventory and setting alerts across many carriers (paid tiers; note some carrier coverage can change). (expertflyer.com)
• SeatSpy — focused award searches and alerts for many European/partner carriers (free tier with limits, low-cost premium plans). (thepointsguy.com)
• Points Path (browser extension) — overlays award vs cash prices in Google Flights so you can compare quickly while searching (free extension). (awardwallet.com)
• MaxMyPoint (hotels) — specialized hotel-award search across major programs (Marriott, Hyatt, Hilton, IHG). Use it for hotel award comparisons. (awardwallet.com)

How to use them effectively

1. Start with a multi-program search engine (Point.me or similar) to see which programs have space and which currencies produce the cheapest bookings. (nerdwallet.com)
2. Confirm and book on the airline’s or partner program’s official site — third-party tools sometimes miss saver/partner-only inventory or can’t book directly. (This is standard practice; see tool descriptions above.) (nerdwallet.com)
3. Set alerts for routes/dates you care about (ExpertFlyer, SeatSpy, or built-in tool alerts) so you’re notified when award seats release. (expertflyer.com)
4. For hotels, run MaxMyPoint or check each program (Hyatt/Marriott/Hilton/ IHG) — hotel tools often cover fewer programs than airline searchers. (awardwallet.com)

Important caveats

• No tool covers every single loyalty program or all partner inventory — you’ll often need to cross-check multiple sources and the issuing program’s site. (awardwallet.com)
• Many of the best award-search features are behind paywalls; free options exist but can be limited. (nerdwallet.com)

If you’d like, tell me a specific route, dates, or which programs you hold and I can suggest the best tool/workflow for that case or run a sample search strategy for you.