Level Adjustment (5e Variant Rule)
From D&D Wiki
As you may or may not know, 5e has largely tried to rid itself of things like level adjustment, for what I feel is a good enough reason. However, due to the prevalence of monstrous races on the wiki, and the demand that everything must be reasonably balanced, some have been gutted in the process, like the slaad and others. While level adjustment is in no way, shape, or form a perfect solution, I believe it could be utilized in order to make certain races more accurate to their source material.
The feature would be worded as such:
Level Adjustment +X. After gaining your first level, you must gain X amount of experience before being capable of gaining experience and leveling up normally.
|Level Adjustment +?||Experience Required|
This goes to a maximum of +3, as by that time another character is 4th level. In doing this, you have some catchup time before you enter the next tier of gameplay.
This should not be higher than 3, or lower than 0 under any circumstance. Negative level adjustment will give you automatic levels, making you an undebatably stronger version of any other race, if you do not introduce massive crippling downsides, and in doing so you remove a large point of taking said race.
Additionally, things get worse when you go higher. The way level adjustment here is handled will keep you at 1st level until you gain enough experience, and reaching the equivalent to 4th level while still only using 1st level equivalent stats is pushing it. If you go further(I.e into the 2nd tier of gameplay, maybe beyond), you have to further account for this difference, keeping them playable by introducing stronger and stronger traits. Since these also apply at 1st level, making a race with Level Adjustment +10 or so is an awful idea.
Musicus Score by Level Adjustment
When using level adjustment, it's a good idea to look at the race's musicus score in regards to where to place their level adjustment. When using level adjustment, aim to give all races a musicus score of 4-5. With that in mind, here's a chart for how level adjustment interacts with the musicus meter.
|Level Adjustment||Musicus Modifier|
When making a race with level adjustment, you must consider the fact that they essentially lose player levels in order to take the race. Measures should be taken accordingly, but don't simply give them class features to compensate, since eventually they may regain these levels. Keep them as strong options but do not overcorrect.