Q:

Crowdsourcing how to tag old and new Delta Green questions

There's a new tag, new-delta-green. Since what's new is relative to now and now keeps changing, that's obviously not a good long-term tag. I'm having a hard time deciding on a replacement though.
So the situation is that the new Delta Green is a full-fledge roleplaying game. The old Delta Green is a line of setting supplements for Call of Cthulhu.
In considering the different ways we disambiguate tags, none of them strike me as sufficiently self-explanatory and “good tagging practice” to be obviously the way to go, leaving me unwilling to just mod-change them unilaterally. The ways I thought of are:

delta-green/delta-green-setting (changing both). This would give primacy to the RPG itself, but these wouldn't get used right: [dg] would keep getting used for both, and [dg-setting] would also get used for both.
delta-green-2016/delta-green (leaving old alone). Old one would get used for the RPG too. It also implies that there was a pre-2016 RPG, so it would be a confusing pair.
delta-green-rpg/delta-green-coc* (changing both). This is clear enough and they likely wouldn't get used wrong, but it's not called “Delta Green RPG” so that rubs me the wrong way. But maybe it's the best of the lot?
(* Notably, delta-green-call-of-cthulhu fits in our tag limit. It might be worth considering instead of delta-green-coc, but it looks to me like the CoC part might overwhelm the DG part. On the other hand, perhaps it should — to emphasise that old DG is a sub-topic of CoC, we might consider call-of-cthulhu-delta-green?)

How should we tag Delta Green the RPG and Delta Green the Call of Cthulhu setting supplement line?

A:

I agree with the principle of not having a generic "delta green" tag left to be confusing and ambiguous.
I suggest we go with delta-green-rpg and delta-green-for-call-of-cthulhu.
delta-green-rpg is the same as what you brought up.
delta-green-for-call-of-cthulhu is better by a hair than the other options for this edition, I think. It comes in at 31 characters (just within our 35 character limit) and clearly establishes the relationship. It also puts "delta green" first, which is the product people are looking for.

A:

delta-green-rpg/delta-green-coc (changing both) Looks the best to me.

This clearly disambiguates the 2 products. 
It forces tag users to pick one or the other, there is no default delta-green to mistakenly choose.
Which tag to use on a given question will be obvious (the acronym and the tag description make it clear)
I think that both tags will be findable by someone searching for them, ie., someone googling "Delta Green Call of Cthulhu" will find and recognize "delta-green-coc".

A:

delta-green-rpg/call-of-cthulhu-delta-green leaves the least scope for confusion.

