[Ayantir]

yes or ..

number numAddons = GetAddonsInstalled()
string addonName = GetAddonName(number index)
boolean isLoaded, string:nilable addonVersion, string:nilable addonAPI, string:nilable addonDescription, string:nilable addonAuthor = GetAddonInfo(addonName)

so we could do

for i, GetAddonsInstalled() do
      local addonName = GetAddonName(i)
      if GetAddonInfo(addonName) then
            -- Addon addonName is loaded !
      end
end

or

if GetAddonInfo("anObviousAddonWhichDontLeakAnyGlobal") then

There is also SavedVars and Depends and and Optional depends on, but it could be a really good start