Wikipedia has a listing of what's included in all the IDW Collections.
en.wikipedia.org
And this has another reading order, for good measure.
This is the most up-to-date timeline of events for the IDW TMNT continuity. Changes will be made as more information is gathered. Upcoming issues are listed in order of publication. Special issues and one-part stories as well as the first mentions of story arcs and miniseries are shown in bold...
turtlepedia.fandom.com
I'm guessing Armageddon Game will get split up into two of these IDW Collections, for volumes 16 and 17. It looks like they have everything included.
Keep in mind, if you have a comic book shop in your area, they MIGHT have a sale around Free Comic Book Day, which is coming up the first Saturday in May. Depends on how many issues you've missed, but if they have a sale on back issues or trades, you might be able to score a pretty good deal, there. Some shops have sales, and some don't, but it always pays to check.