Gorm the Great - An inefficient beater that can only pick off summoning sick dorks. Because of this reason, Gorm is relegated to Tier 5 when alone.
Ishai, Ojutai Dragonspeaker - Similar to Geist of Saint Traft, Ishai seems to point to a UW beatstick plan. As this suffers from the aggro problem of EDH (dealing 63 commander damage), the voltron route will not lead to higher initial placement. Since you cannot force your opponents to cast spells, Ishai grows unreliably. Had it been a 1 or 2 drop, then you could cash in on your opponents casting mana rocks and dorks, but at 4 mana, Ishai will not grow fast enough to outrace combo/stax players. Because of these reasons, Ishai is relegated to Tier 5 when alone.
Khorvath Brightflame - Here we have a Knight tribal commander in Mono-Red. Six mana is extremely slow to accomplish anything meaningful with this already weak ability. Because of these reasons, Khorvath is relegated to Tier 5 when alone.
Ludevic, Necro-Alchemist - Don't give your opponents free cards...like ever...also, his flavor is disappointing. Because of these reasons, Ludevic is relegated to Tier 5 when alone.
Sylvia Brightspear - Mono-White Dragons. No. Because of this reason, Sylvia is relegated to Tier 5 when alone.
Akiri, Line-Slinger - As a voltron commander Akiri has some potential. With a built-in Cranial Plating, Akiri benefits from artifacts ranging from Sol Ring to Ancient Den to Inquisitor's Flail. Because of this reason, Akiri is relegated to Tier 4 when alone.
Bruse Tarl, Boorish Herder - Like Akiri, Bruse Tarl has the potential for a decent voltron deck. The built-in double strike allows him to close out games fast(-ish). Because of this reason, Bruse Tarl is relegated to Tier 4 when alone.
Ikra Shidiqi, the Usurper - Ikra is kind of bad, but 7 life is not irrelevant when it comes to Necropotence and Ad Nauseam. If the The Gitrog Monster (I made a funny) can be ramped out fast enough to be useful, then Ikra can also be relevant. Because of these reasons, Ikra is relegated to Tier 4 when alone.
Pir, Imaginative Rascal - Pir has an interesting effect, probably best with planeswalkers such as Nissa, Vital Force and artifacts such as Shrine of Boundless Growth. As his effect is quite unique and works with all permanent types, Pir can probably accomplish quite a few interesting things. Because of these reasons, Pir is relegated to Tier 4 when alone.
Regna, the Redeemer -
Reyhan, Last of the Abzan - Reyhan is pretty cool, especially with Blade of Selves. While not as versatile as Ghave, Guru of Spores, she can do similar shenanigans with counters. While she does not seem to have the capacity to be truly competitive, a good enough build of her may land her in Tier 3. However, I do not know if people would be willing to invest time into finding how to break her. She has potential, given her colors and synergy. Because of these reasons, Reyhan is relegated to Tier 4 when alone.
Rowan Kenrith -
Sidar Kondo of Jamuraa - Sidar Kondo enables attacker shenanigans, similar to Edric, Spymaster of Trest. However, because Sidar Kondo does not have blue (nor card advantage), there is a limit to the number of combat damage shenanigans he can enable. He enables creatures like Centaur Rootcaster and Avenging Druid, making him have more utility than your average Tier 5 trash. Ophidian is an example of the time of effect he can enable when you expand his color identity. Because of these reasons, Sidar Kondo is relegated to Tier 4 when alone.
Toothy, Imaginary Friend -
Vial Smasher the Fierce - Vial Smasher is a relatively unimpressive commander. Because her damage is random, it mostly amounts to some minor upside that has a chance of killing a planeswalker. However, in a deck that is made to cast arbitrarily large X spells (through permanent-based combos), Vial Smasher can kill random opponents. For example, If you assemble Grave Titan, Ashnod's Altar, and Nim Deathmantle, you can kill two opponents with a Maga, Traitor to Mortals. However, because your opponents will not let you get to your turn to cast an arbitrarily large sorcery/creature, you would need to run clunky instants such as Starstorm or Street Spasm to kill (random) opponents on (random) upkeeps. This is rather unreliable, but still functions decently enough. Because of these reasons, Vial Smasher is relegated to Tier 4 when alone.
Virtus the Veiled -
Will Kenrith -
Kraum, Ludevic's Opus - Kraum is an interesting commander. He is a 4/4 flyer with haste, making him able to pressure planeswalkers and, if left unchecked, opponents' lifetotals. Kraum dissuades your opponents from casting multiple spells, lest you benefit. He is similar to Mystic Remora in this respect, though he is weaker since he does not stack. Being a 5-drop also makes him less powerful, as, like Ishai, he does not benefit from the early turns when your opponents are casting mana rocks and dorks. Regardless, he is a soft stax piece that draws cards, making him right at home in cEDH. Because of these reasons, Kraum is relegated to Tier 3 when alone.
Kydele, Chosen of Kruphix - Kydele is a mana dork with massive upside. Like numerous Elf-ball combos, Kydele has the ability to make an infinite mana with artifacts such as Umbral Mantle and Staff of Domination. If you can draw a bunch of cards in one turn, you now have infinite mana. Can you name a good way in Blue/Green to draw a bunch of cards? I can: Brainstorm, Timetwister, Stroke of Genius, Blue Sun's Zenith, Windfall. Even Breakthrough may have a place in the deck! The list goes on. When she is not comboing out, Kydele is a mana dork that produces , but with minimal support, she can easily produce or per turn. She has a great color identity and, since mana is always great, an ever-relevant ability. Because of these reasons, Kydele is relegated to Tier 3 when alone.
Ravos, Soultender - Ravos is a blend between Glorious Anthem and Oversold Cemetery, making him able to support both go-wide and go-tall strategies. He can also recycle useful effects such as Shriekmaw or get back hatebears such as Thalia, Guardian of Thraben. Ravos is surprisingly versatile despite having such seemingly lukewarm effects. Because of these reasons, Ravos is relegated to Tier 3 when alone.
Silas Renn, Seeker Adept - Silas Renn allows you to recur artifacts from your graveyard. Think of him as a slower Sharuum the Hegemon. You can recycle a Executioner's Capsule and Dispeller's Capsule to deal with problem permanents, get back fodder for Smokestack, and otherwise gain card advantage. Because there are many creature-light cEDH decks, Silas Renn is not unlikely to always be able to get in. Additionally, because he has deathtouch, that annoying Zur player cannot just cast Zur and block forever. Because of these reasons, Silas Renn is relegated to Tier 3 when alone.
Tana, the Bloodsower - Tana is easily one of the premier Stax commanders of C16. Because of her ability to create extra permanents, she can break parity with cards like Tangle Wire, Possessed Portal, and Smokestack. Additionally, because the tokens she makes are creatures, Tana can draw value from cards like Fecundity and Ashnod's Altar to pull ahead of opponents. Because of these reasons, Tana is relegated to Tier 3 when alone.
Tymna the Weaver - Tymna is what a good Red-White commander would look like: cares about combat, resolves the card draw problems. Tymna is an aggro commander similar to Karlov of the Ghost Council, but instead of being the removal of the deck, she is the card advantage. She can run value creatures and hatebears to slow opponents and grind out games. While not being optimal to a Stax deck, she could be the head of a Midrange deck centered around a Bomberman kill, which she digs to with her ability.
Thrasios, Triton Hero - Easily the strongest of all the partners. Thrasios is an infinite mana sink that results in a win. Since he even works with infinite colorless, he is one of the simplest sinks to exploit. You can use Monolith combos, Palinchron combos, or even Bomberman (well, once you open up his color identity :P ) to achieve infinite mana, activate Thrasios a few times, and drop an arbitrarily large Walking Ballista, or something else. You can even activate Thrasios for value. Since he is a two drop, getting him out is easy. You never have to feel bad about leaving up mana for interaction since you can activate him if no one does anything worth stopping. Since most of the other partners were intentionally given half the strength of a normal legendary creature (making the majority of them the disappointments that they are), everyone was surprised by Thrasios, as he is so close to a full fledged powerhouse on his own. His nerf was probably the . As a non-partner commander, his activation likely would have been . Also, he is a Merfolk, so of course he is the best. Because of these reasons, Thrasios is relegated to Tier 2 when alone.