diff --git a/__init__.py b/__init__.py
index 642ab7c..1f13937 100644
--- a/__init__.py
+++ b/__init__.py
@@ -36,9 +36,12 @@ class SocialSiteId(enum.Enum):
     CARRD_PAGE = 24
     HENTAI_FOUNDRY = 25
     YOUTUBE_CHANNEL_HANDLE = 26
+    YOUTUBE_CHANNEL_ID = 2397
     VIMEO_CHANNEL = 27
     NEWGROUNDS_PAGE = 28
     ARTSY_ARTIST = 2042
+    LINK_COLLECTION_PAGE = 29
+    DEVIANT_ART_ACCOUNT = 7737
 
     def wikidata_property(self, client):
         return client.get(WIKIDATA_PROPERTIES[self])
@@ -80,7 +83,7 @@ WIKIDATA_PROPERTIES = {
     SocialSiteId.TIKTOK_USER: WikidataInfo(7085, None),
 
     SocialSiteId.PIXIV_USER: WikidataInfo(None, 306956),
-    #SocialSiteId.MASTODON_PAGE: 2000 + 10,
+    SocialSiteId.MASTODON_PAGE: WikidataInfo(4033, None),
     SocialSiteId.PATREON_PAGE: WikidataInfo(4175, 15861362),
     SocialSiteId.ARTSTATION_PAGE: WikidataInfo(None, 65551500),
     #SocialSiteId.INPRNT_PAGE: WikidataInfo(None, None),
@@ -88,9 +91,11 @@ WIKIDATA_PROPERTIES = {
     SocialSiteId.CARRD_PAGE: WikidataInfo(None, 106036503),
     SocialSiteId.HENTAI_FOUNDRY: WikidataInfo(None, 115903301),
     SocialSiteId.YOUTUBE_CHANNEL_HANDLE: WikidataInfo(11245, 866),
+    SocialSiteId.YOUTUBE_CHANNEL_ID: WikidataInfo(2397, None),
     SocialSiteId.VIMEO_CHANNEL: WikidataInfo(4015, 156376),
     SocialSiteId.NEWGROUNDS_PAGE: WikidataInfo(None, 263655),
     SocialSiteId.ARTSY_ARTIST: WikidataInfo(2042, 4796642),
+    SocialSiteId.DEVIANT_ART_ACCOUNT: WikidataInfo(7737, None),
 }
 
 def re_social_subdomain(main_domain):
@@ -104,6 +109,7 @@ def re_social_path(main_domain):
     return re_social_path_adv(main_domain, RE_ID)
 
 def re_social_path_adv(main_domain, *path):
+    assert not main_domain.startswith('www.'), 'Redundant www.'
     l = [r'^', '(?:https?:\/\/)?', r'(?:www\.)?', re.escape(main_domain)]
 
     for p in path:
@@ -139,9 +145,13 @@ URL_PARSE_CARRD_PAGE = re_social_subdomain('carrd.co')
 URL_PARSE_HENTAI_FOUNDRY= re_social_path_adv('hentai-foundry.com', 'user', RE_ID, 'profile')
 URL_PARSE_YOUTUBE_CHANNEL_HANDLE_1= re_social_path_adv('youtube.com', RE_ID)
 URL_PARSE_YOUTUBE_CHANNEL_HANDLE_2= re_social_path_adv('youtube.com', 'c', RE_ID)
+URL_PARSE_YOUTUBE_CHANNEL_ID= re_social_path_adv('youtube.com', 'channel', RE_ID)
 URL_PARSE_VIMEO_CHANNEL= re_social_path_adv('vimeo.com', RE_ID)
 URL_PARSE_NEWGROUNDS_PAGE = re_social_subdomain('newgrounds.com')
 URL_PARSE_ARTSY_ARTIST = re_social_path_adv('artsy.net', 'artist', RE_ID)
+URL_PARSE_DEVIANT_ART_ACCOUNT = re_social_path_adv('deviantart.com', RE_ID)
+URL_PARSE_DEVIANT_ART_ACCOUNT_2 = re_social_subdomain('deviantart.com')
+# TODO: https://<ID>.deviantart.com
 
 REGEXES = [
     # Reddit
@@ -214,6 +224,7 @@ REGEXES = [
     # Youtube
     (URL_PARSE_YOUTUBE_CHANNEL_HANDLE_1, SocialSiteId.YOUTUBE_CHANNEL_HANDLE),
     (URL_PARSE_YOUTUBE_CHANNEL_HANDLE_2, SocialSiteId.YOUTUBE_CHANNEL_HANDLE),
+    (URL_PARSE_YOUTUBE_CHANNEL_ID, SocialSiteId.YOUTUBE_CHANNEL_ID),
 
     # Vimeo
     (URL_PARSE_VIMEO_CHANNEL, SocialSiteId.VIMEO_CHANNEL),
@@ -223,8 +234,32 @@ REGEXES = [
 
     # Artsy
     (URL_PARSE_ARTSY_ARTIST, SocialSiteId.ARTSY_ARTIST),
+
+    # Deviant art
+    (URL_PARSE_DEVIANT_ART_ACCOUNT, SocialSiteId.DEVIANT_ART_ACCOUNT),
+    (URL_PARSE_DEVIANT_ART_ACCOUNT_2, SocialSiteId.DEVIANT_ART_ACCOUNT),
 ]
 
+WELL_KNOWN_MASTODON_INSTANCES = frozenset({
+    # Includes all servers with 50 000+ users as of 6 july 2023.
+    # based on https://mastodonservers.net/servers/top
+    'mastodon.social',
+    'pawoo.net',
+    'baraag.net',
+    'mstdn.jp',
+    'mastodon.cloud',
+    'mstdn.social',
+    'mastodon.online',
+    'mas.to',
+    'mastodon.world',
+    'mastodon.lol',
+    'mastodon.sdf.org',
+    'c.im',
+    'mastodon.uno',
+    'mastodonapp.uk',
+    'fosstodon.org',
+})
+
 def determine_social_from_url_internally(url):
     assert isinstance(url, str)
 
@@ -235,6 +270,9 @@ def determine_social_from_url_internally(url):
             return (social_site_id, groups[0] if len(groups) > 0 else None)
 
     # Mastodon
+    for mastodon_hostname in WELL_KNOWN_MASTODON_INSTANCES:
+        if url.startswith('https://' + mastodon_hostname):
+            return (SocialSiteId.MASTODON_PAGE, None)
     if 'mastodon' in url:
         return (SocialSiteId.MASTODON_PAGE, None)
 
@@ -266,6 +304,8 @@ def run_tests():
     assert determine_social_from_url('https://www.tiktok.com/@depthsofwikipedia?lang=en').social_id == 'depthsofwikipedia'
     assert determine_social_from_url('https://www.pixiv.net/users/14866303').social_id == '14866303'
     assert determine_social_from_url('https://www.pixiv.net/member.php?id=109710').social_id == '109710'
+    assert determine_social_from_url('https://www.deviantart.com/solquiet').social_site_id == SocialSiteId.DEVIANT_ART_ACCOUNT
+    assert determine_social_from_url('https://solquiet.deviantart.com/').social_site_id == SocialSiteId.DEVIANT_ART_ACCOUNT
 
     INSTAGRAMS = [
         'https://instagram.com/_richardparry_',