I've a slower cube. It's focused more around battlecruiser/EDH-ish with casting and wrecking people with large dragons. A good way to summarize it is I've put Worldspine Wurm into a deck without any ways to cheat it into play and cast it.
Since I don't support Mono-R aggro a whole lot, my red section struggled with a distinct identity. I tried a goblin subtheme but that didn't stick. I tried artifact synergies, but blue just did that better. However, I really like Chandra, so I've been putting a bunch of Chandras in my cube. So one of red's sub-themes was that while every other color is capped on planeswalkers at 3. Red gets basically as many playable Chandras as they print. Which until recently was basically Chandra, Torch of Defiance, Chandra, the Firebrand, and Chandra, Flamecaller. I'm also running Chandra Nalaar and Chandra, Fire of Kaladesh because even though my friends think they're complete trash. They're actually 23rd card playable in my cube. Anyway they just printed Chandra, Fire Artisan and Chandra, Awakened Inferno who are also super strong and I'm adding.
I'm actively maintaining a comprehensive article to help explain to new cube players how some complex vintage level cards work in a cube environment. Vintage Cube Cards Explained
Since I don't support Mono-R aggro a whole lot, my red section struggled with a distinct identity. I tried a goblin subtheme but that didn't stick. I tried artifact synergies, but blue just did that better. However, I really like Chandra, so I've been putting a bunch of Chandras in my cube. So one of red's sub-themes was that while every other color is capped on planeswalkers at 3. Red gets basically as many playable Chandras as they print. Which until recently was basically Chandra, Torch of Defiance, Chandra, the Firebrand, and Chandra, Flamecaller. I'm also running Chandra Nalaar and Chandra, Fire of Kaladesh because even though my friends think they're complete trash. They're actually 23rd card playable in my cube. Anyway they just printed Chandra, Fire Artisan and Chandra, Awakened Inferno who are also super strong and I'm adding.
Since they just printed Chandra, Acolyte of Flame and Chandra's Regulator I was thinking of "officially" supporting "Chandra Tribal" as a one of Red's color identities. Is there any other good synergy cards like these I should consider adding? I'll probably get Oath of Chandra, Chandra's Phoenix, and Chandra's Triumph. Anything else I should consider?
The Ur-Dragon (WUBRG) - Changeling Combo Tribal
Chromium (WUB) - Artifact Beats
Progenitus (WUBRG) - Dredge
Damia, Sage of Stone (GBU) - Elf-storm Tendrils
My Cube Unpowered
My Peasant-ish/Tribal-ish Cube
I just did a quick search on gather - https://gatherer.wizards.com/Pages/Search/Default.aspx?name= [Chandra]
https://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=466883 seems like a card you might want to consider. But in all honestly, the Chandra abilities are work well with cheap burn spells (spells matters archetypes). I think that might be the better approach
Vintage Cube Cards Explained
Here are some other articles I've written about fine tuning your cube:
1. Minimum Archetype Support
2. Improving Green Archetypes
3. Improving White Archetypes
4. Matchup Analysis
5. Cube Combos (Work in Progress)
Draft my Cube - https://cubecobra.com/cube/overview/d8i