Is your feature request related to a problem? Please describe.
I tend to go to https://www.wowhead.com/icons to grab certain icons that are not available within weakauras like https://www.wowhead.com/icon=2032225 and I'd prefer not having to do that extra step

Describe the solution you'd like
After the user inputs a name, iterate over all achievements and show the icons of achievements that contain the user's input in their name

Describe alternatives you've considered
https://www.wowhead.com/icons/

Additional context
This code can be used to to obtain iconID and achievement name:

for k,v in pairs(GetCategoryList()) do
   local total = GetCategoryNumAchievements(v, true)
   for i = 1, total do
      local _,name,_,_,_,_,_,_,_,iconID = GetAchievementInfo(v, i)
      if name and iconID then 
         --if user input contains parts of av name then show icon..
      end
   end
end

According to print, it adds 2902 icons (1963 unique icons after filtering same iconID)

Well, that's not exactly a PR, is it? Nor does it contain any information how long that fetching takes.