Updated UB Shadow deck for modern format.
Using Murktide Regent and Psychic Frog synergic package.
Deck has classic hand disruption, counter magic, removal spells. Draw cantrips.
Threats are Death's Shadow, Murktide Regent and Psychic Frog.
For utility and additional value there is Snapcaster Mage.
Utility spells like Archmage's Charm, Cling to Dust - instant targeted grave hate, can be used for additional card draw or life gain (in games against very aggressive decks and decks running lightning bolts...), possible synergy with Murktide in play via escape mechanic.
Card Psychic Frog works really well in this deck doing a lot of things - Filling grave for Murktide (or provides at least some usage for cards which you do not need at the moment via discard and +1/+1 Frog), synergy with Murktide in play with possibility to remove cards from you graveyard and trigger Murktide +1/+1, draw engine.
Psychic Frog seems to be main utility / support piece in the deck.
Land Castle Locthwain is used for additional draw and life loss, Creeping Tar Pit is additional unblockable threat.
Sink into Stupor
is nice universal tempo card / land with possible life loss for Shadow.
Updated sideboard:
+1 Consign to Memory / -1 Disruptor Flute,
+2 Unlicensed Hearse / -2 Stone of Erech,
+2 Tourach, Dread Cantor / -1 Disruptor Flute -1 Cling to Dust,
There is in general better synergy with Unlicensed Hearse since there are Drown in the Loch in the deck and Snapcaster Mage can crew the Hearse.
If needed Hearse can exile cards from own graveyard to help grow Murktide Regent on the battlefield.
