I have found resources that suggest heroes to counter The Butcher (e.g. https://www.heroescounters.com/hero/thebutcher), but not a list of heroes that can escape Ruthless Onslaught specifically and how they do it, similar to Which heroes can escape Zarya's ult?.
When a hero is charged by the Butcher, they can avoid it by entering stasis, by becoming invulnerable somehow, or by escaping behind the walls or an unpathable for enemy heroes (like the Hall of Storms), or maybe leading the Butcher into Chromie's hourglasses or Zeratul's VP, and escaping where he can't reach them as I just wrote.
- For the invulnerability, you either need a Tyrael or Uther with Sanctification or Divine Shield as an ultimate on your team. Or if you're Johanna, you can use the Falling Sword ultimate when he charges at you and disappear into the sky. You can also do so as a Metamorphosis Illidan, Genji's X-Strike, Murky's Safety Bubble, The Lost Viking's Jump/Longboat or use Tracer's Rewind. Those will cancel the Butcher's charge and make it enter full cooldown.
- For the stasis, Dehaka has an built-in stasis in his kit (Burrow). You can also use Ice Block or something equivalent to it, that includes Jaina, Chromie, Nazeebo, i think Kerrigan too? Or you can also run into a Zeratul VP or have an Auriel stasis you. At worse, you can run into a Chromie time trap, but I would advise against it. Entering stasis while charged by the Butcher will also cancel it and make it enter full cooldown.
- And finally, escaping the charge itself, you need to be a mobile hero. Genji is the first one that comes to mind as his E makes him dash half the screen. If the gates or the walls aren't down yet, you can E to safety and see him run into tower's range. You can also do so with Hanzo's wall jump, Muradin's Dwarf Toss, helped by Garrosh's Into the Fray if he picked it, Junkrat's mine to safety. Note that if you're able to outrun him for long enough, the charge will cancel itself after a certain time, making it enter full cooldown.
You may not have asked for it, but you can also negate the stun with any Unstoppable granting spells. Such as Johanna's trait, Garrosh's Indomitable (?), Diablo's Lightning Breath, Alarak's Counter Strike or an ally's Cleanse-like ability (Uther/Lili).
If others have more to add to this list, please do
- Every hero that can go to stealth (Nova, Tassadar, Valeera, Samuro, Zeratul ...).
- Every hero that can TP away on demand (Chromie, Brightwing, Tracer, Fenix)
- Every hero that can go into stasis (Jaina, Nazeebo)
- Every hero that can become invulnerable (Johanna, Murky)
- Medivh when turning Raven.
- Dehaka with Burrow
- Auriel casting Stasis on you
- Mal'Ganis with Night Rush or Carrion Swarm
Unsure but possible:
- Genji with Cyber Agility
- Maiev with Vault of the Wardens
- Greymane with Shapeshift
- Sylvanas with Haunting Wave and Teleport
- Leoric with Wraith Walk
I'm sure that is by far not complete. As you can also see the list of heroes where I'm not sure is pretty long. But I thought I'd at least start with something which can be refined then.