I usually would recommend/prefer to create my own 1.8.8 modpack and pick between mods but also 1.8.9 is the superior version if you want a good modpacks of a big scale (popular or big mods even for big scale is my guess), even big mods were trying to adjust at the time like Tinker's Construct 2 wasn't great for 1.8.8, it might have been available but it was still being worked out and features weren't ready (that being smeltery features that worked in the past, at least from my memory of experiences with 1.8.8 and Tinker's 2 when 1.8.8 was new). Depends on the mod offerings your looking for though, there are tons out there to choose from, but many big mods or modpacks (popularity or content) you aren't going to find for 1.8.8.
At least I think so. Eating words as looking through 1.8.8 mod support... Anyways, modpack offerings below.
For a look at those that state specific 1.8.8 not version 1.7.10 to 1.8.8 work and so many version tags its ridiculous. Here are what I found. Check the mod offerings if you want of course. A good amount of well known/popular mods were in here, but I'd say 1.8.9 is superior due to 1.8.8 being a short version and shorter on modpacks/mods supporting it.
Modpacks I believe by looking at, at least to be 1.8.8 (not tried any of these myself, just ones I think legit are for 1.8.8)
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