MC Cartridges which fit rega arm.

You can always stay with Rega--

Rega Apheta (if you want to spend a larger sum of money)

Rega Exact

Both of these will be upgrades over your current Elys.

******I am a Rega Dealer******

I got fantastic result with Denon DL 304 on the Michell Tonearm (kinda super Rega 250)

Don't let Roy Gandy limit your choice of cartridges! There are a number of aftermarket products that let you adjust VTA on Rega arms:

Michell
Origin Live
Galibier
Pete Riggle
VPI
Sound Supports

I've used the Michell sleeve and it works very well. In terms of cartridge recommendations, you need to tell us your budget (new or used?) and what phono stage you'll be using.