I'm happy Griselbrand was dealt with swiftly. I'm unhappy that Sundering Titan was axed. The two stated reasons for it are
One, it simply created undesirable game states. It was too easily both intentionally abused and unintentionally game-warping, especially since its ability triggers on both entering and leaving the battlefield. Two, there has been a fair amount of community distaste for the card, and we agreed that the card overwhelmingly creates a negative experience for players.
Undesirable for who? Not the person playing the Sundering Titan. Nobody desires a game state that causes them to lose. Should we ban everything else that creates undesirable game states too? Well, only if there is a fair amount of community distaste for the card too, right? Which community? Isn't that exactly why house bans exist, so individual playgroups can decide at their own discretion? That's where some of my ire lies: my playgroup is online, I have no option to use house rules to fix these problems created by the RC. Vaguely defined community distaste and undesirable game states form a reasonable case for banning cards in this format now, what a slippery slope that is. I fully expect all MLD and resource denial to be banned in the future if the RC maintains the perspective that got Sundering Titan banned.
I've used Maralen of the Mornsong + Teferi's Puzzle Box as part of a nasty lock, but not with her as a commander. Flash in Teferi, Mage of Zhalfir followed by Maralen right before your turn, use Maralen to tutor up the Box. Unless an opponent has a cycling card or something on the board that can be activated to stop you, your opponents will lose their hands, won't get any new cards at all, and won't be able to cast anything they tutor before having it tucked. Meanwhile, you get to tutor a card per turn to deal with any remnants of board presence they had, a Plague Wind will usually suffice. They can still cast their commanders, but all you have to do is tutor up bounce to tuck them with the Box. Pick your wincon from there. My favorite part about this combo is how it only takes 1 card to enable the entire thing: Mystical Teachings. Teachings finds Teferi, then once Teferi is in play the flashback of Teachings can find Maralen.
Sol'kanar the Swamp King will always hold a special place in my heart as he was my first commander. He's a fairly-costed Grixis beater with good evasion and he might even gain you a few life, but the best thing about him is how nonthreatening he appears. You can play all sorts of cruel and swingy spells in Grixis, but if you're not playing Thraximundar people tend to underestimate your deck.
Flash in Teferi followed by Maralen before your turn starts so you get the first tutor off Maralen. Tutor for Puzzle Box, play it. Stack the triggers so that your opponents tuck their hands after they tutor, opposite for you. Your opponents are now limited to any activated abilities they had on the board before Teferi hit as well as their commanders, but you get to tutor each turn for your choice of solutions to those, such as bounce to tuck their commanders with the Puzzle Box.
I love this combo because it's completely tutorable via Mystical Teachings and difficult to disrupt. If you're patient you don't even have to telegraph it. Once you're at 13 mana you can use Teachings to find and play Teferi before your turn, then flashback the Teachings to find and play Maralen during your upkeep, then tutor and play Puzzle Box with the remaining 4 mana.
My Godo deck loves Nim Deathmantle. It's almost always my first fetch with him. With Ashnod's Altar out, I only need to sac/reanimate Godo 3 times to bring out the Kaldra set, which in turn generates infinite colorless mana and allows me to pay for Godo's reanimation to fetch every piece of equipment in the deck.
I've run into this problem on MTGO and reported it as a bug, but I figure it's worth double checking to make sure I understand how it's supposed to work.
When I cast Memory Plunder or use Wrexial, the Risen Deep's ability and target an opponent's Recollect in their graveyard MTGO will only allow me to select from cards in that opponent's graveyard after casting the Recollect. This always results in an illegal target since I can't take their card into my hand using Recollect.
The way I see it, I'm casting the Recollect so it should only target my own graveyard. Am I wrong or is this a bug?
Undesirable for who? Not the person playing the Sundering Titan. Nobody desires a game state that causes them to lose. Should we ban everything else that creates undesirable game states too? Well, only if there is a fair amount of community distaste for the card too, right? Which community? Isn't that exactly why house bans exist, so individual playgroups can decide at their own discretion? That's where some of my ire lies: my playgroup is online, I have no option to use house rules to fix these problems created by the RC. Vaguely defined community distaste and undesirable game states form a reasonable case for banning cards in this format now, what a slippery slope that is. I fully expect all MLD and resource denial to be banned in the future if the RC maintains the perspective that got Sundering Titan banned.
Backlash doesn't kill via general damage since that must be dealt as combat damage.
I have a few that aren't quite instant reversals, but they tend to come out of nowhere (read: someone's hand) for wins:
Sun Quan, Lord of Wu can be a great surprise when people think they've got blockers lined up.
Vulshok Battlemaster can turn all those pretty toys on the board into someone's death knell.
Tainted Strike has already been mentioned, but its cousin Triumph of the Hordes can be a big surprise as well.
I'm a big fan of RKF's work.
Teferi, Mage of Zhalfir+Maralen of the Mornsong+Teferi's Puzzle Box
Flash in Teferi followed by Maralen before your turn starts so you get the first tutor off Maralen. Tutor for Puzzle Box, play it. Stack the triggers so that your opponents tuck their hands after they tutor, opposite for you. Your opponents are now limited to any activated abilities they had on the board before Teferi hit as well as their commanders, but you get to tutor each turn for your choice of solutions to those, such as bounce to tuck their commanders with the Puzzle Box.
I love this combo because it's completely tutorable via Mystical Teachings and difficult to disrupt. If you're patient you don't even have to telegraph it. Once you're at 13 mana you can use Teachings to find and play Teferi before your turn, then flashback the Teachings to find and play Maralen during your upkeep, then tutor and play Puzzle Box with the remaining 4 mana.
Have you considered Goblin Warrens? It fits your goblin token theme very well and further enables your ETB engines.
If a creature takes lethal damage from the creature equipped with Sword of Kaldra, does the creature hit the graveyard or is it exiled?
When I cast Memory Plunder or use Wrexial, the Risen Deep's ability and target an opponent's Recollect in their graveyard MTGO will only allow me to select from cards in that opponent's graveyard after casting the Recollect. This always results in an illegal target since I can't take their card into my hand using Recollect.
The way I see it, I'm casting the Recollect so it should only target my own graveyard. Am I wrong or is this a bug?