I found that most stats websites don't show stats for ARAM or show very limited ones, so I created ARAM Zone, a website focused on ARAM.
It's similar to other stats-based websites but I've tried to add my own extra twist to it. Specifically, for champion details and the champion tierlist screens I've divided champions by the main rune and first item bought. AP Malphite is VERY different than tank Malphite so I thought it was silly to group them as one. In Malphite's case, AP builds have 45-49% win rate and tank builds 55-60% win rate, which is very relevant info when deciding what to build!
You can also search for your Summoner name and see your personal stats on ARAM :)
Anyways, if there are any League fans here and you give it a shot let me know what you think!