Before I even start, the obvious answer is a Flow Ex or old-stock Flow, this I know
My rear Flow Ex is dead- it's got a big flat spot and won't safely hold a tyre on tubeless. It's a Hope Hoops, Pro 2 with I think comps, and it's been impressively troublefree otherwise so I'm planning to reuse the spokes as they seem in good nick. I'm selling the dh bike so this is going to end up being a hard-use spare/alps wheel for the Hemlock to spare its crabonz from uplift days, and will probably find a permanent home in a Patriot 66 or something for cheap uplift bashing once I have the cash
Generally I was more impressed with the Flow than the Ex, I've destroyed one of each but the Flow lasted much longer and seemed to shrug off damage more. The Ex seems good but the low bead seems to mean it doesn't take a lot of dent to cause real problems.
But I don't begrudge that the rim's failed as it's had hard enough use to justify it (it took the fatal blow at the endurance downhill race at fort william)
So... Anything else with comparable ERD, tubeless ready, as strong as or stronger? I'd thought 821 but the ERD looks to be too different to fit with the same spokes... But then ERD figures aren't always totally accurate and Mavic seem to want to keep it secret!