You won’t get notifications, but anything that is included in your watchlist will appear in the my:watched
query; think of it as the “subscriptions” page on youtube. And it’s not only singular tags that you can “watch”, you can also add complex expressions to your watchlist, in the section titled “Watch list search string”; for example if you want to “watch” images where both Sweetie Belle and Rarity appear, you can use
(sweetie belle && rarity)
, and images that have both tags will appear in your “my:watched” query. For more information on expressions you can look at the search syntax
page, you can add pretty complex tag combos if you are so inclined.