Gee76’s wheels are as good as you’ll get for the money (largely cos they’re more expensive wheels in the first place, but also cos DT make awesome wheels).
Other than that, Fulcrum/Campag (same company) make probably the stiffest ally clinchers going. I’ve got some Eurus (Racing 1’s) on my bike, they’re awesome! But they’re not perfect (more hassle maintenance wise than some)
The Novatec Jetfly’s are incredible for the money. The performance per £ seemingly unmatched unless you find some more expensive wheels heavily discounted.
Decide on your priorities… Mine was that they had to be as stiff as I could get, and tubeless ready, weight and ease of service were secondary considerations to me, hence the Eurus’. Your priorities may be different.