Is this homebrew gnoll race balanced?

Question

I've been tinkering with a gnoll race and I've been wondering whether it's balanced or not. I want to hear your thoughts on so I can possible revise it in the future. The traits are mainly based on abilities of real life hyenas.

• Ability Score Increase. Your Strength score increases by 2, and your Dexterity score increases by 1.
• Darkvision. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.
• Size: Medium
• Speed: 30 ft.
• Rampage. When you reduce a creature to 0 hit points with a melee attack on your turn, you can take a bonus action to move up to half your speed and make a bite attack.
• Heart of the Hunt. You can add twice your proficiency bonus to any Strength (Athletics) checks related to chases and running.
• Keen Smell. Thanks to your sensitive nose, you have advantage on Wisdom (Perception), Wisdom (Survival), and Intelligence (Investigation) checks that involve smell.
• Bite. You have a fanged maw that you can use to make unarmed strikes. When you hit with it, the strike deals 1d6 + your Strength modifier piercing damage , instead of the bludgeoning damage normal for an unarmed strike.
• Languages. You can speak, read, and write Common and Gnoll.

Answer 1

Some of your verbiage is a little odd, and I have a couple changes, but it should be

Balanced for general play

This feels like you went off of the Lizardfolk as a template (not a criticism, it's where I would have started). I think this is pretty well done and I wouldn't have an issue playing alongside it at my table.

ASI, Speed, Vision, Languages, and Size are all standard - so I'm not going to talk further on it.

• Bite is fine. It's really not going to get that much use.
• Rampage I think that rampage being limited to your bite attack is important here.
• Heart of the Hunt is clunky and I'd recommend it being proficiency instead. Not many traits give expertise (it's usually advantage) and also it's a niche application. Maybe Proficiency in Wisdom (Survival).
• Keen Senses is also clunky. I know the Loxodon has this, but that's an entire extra appendage and the schtick of the race; the standard way to do for player races it is to give a proficiency in Wisdom (Perception). Advantage on scent checks and the like is more for monsters - and even then it's just "Wisdom (Perception) related to Smell/Hearing".

To reiterate: I don't think that Heart of the Hunt is terribly strong, but it's just not going to get much use as you have it. I have never ever had to roll Strength (Athletics) to run or chase and I haven't seen anyone do it either. Keen Senses is a little stronger than I'd like and I do recommend toning it down, but my issue is that it feels out of place. That's not to say that you can break the mold a little bit when making new things, but there should be some consistency in feeling across abilities across races.

Answer 2

Can use some small tweaks, but overall looks good

Overall what you have looks relatively balanced, if compared with other monster races. I will use the Bugbear from Volo's Guide to Monsters as a benchmark:

• Ability Score Increase. Identical. OK.
• Darkvision. Identical. OK.
• Size: Medium. Identical. OK.
• Speed: 30 ft. Identical. OK.
• Rampage. This is a damage increase, in itself very strong. Compare the Bugbear which has situational +2d6 damage, this is going to do a lot more, and possibly more often. At very high levels or with feats there may be other ways to get a bonus action attack, but still, the rest of the features should be weaker if you retain this.
• Heart of the Hunt. Expertise is potentially bounded Accuracy breaking and therefore also strong but the scope is very narrow. This is roughly on par with the Bugbear's Sneaky.
• Keen Smell. This seems to be overdoing it. Nearly any monster with Keen Smell I have seen has this text: (Monster Name) has advantage on Wisdom (Perception) checks that rely on smell. I would leave it at that. This is weaker then the Bugbear's Long-Limbed and helps to balance, but perception still is one of the most useful skills.
• Bite. The MM Gnoll bite has d4, not d6, so I would stay with that to be consistent. If done that way, it does only 1.5 expected damage more than a normal attack, and is weaker than using the weapon attack anyways, so OK.
• Languages. Identical (with Gnoll instead of Goblin). OK

The Bugbear in addition has Powerful Build which is a strong continuous benefit, so I would say this is even overall, a bit on the strong side.