class progression through a feat

[Horas Ebonfeather]

Is there a feat that allows some class progression while taking a different class?

I know that there was two different feats in 3.5 that allowed that,
example:

tashalatora monk: Benefit: Your levels in the psionic class you selected for Monastic Training stack with your monk levels to determine your AC bonus, flurry of blows attacks, and unarmed damage from the monk class.

swift hunter: Benefit: Your ranger and scout levels stack for the purpose of determining the extra damage and bonus to Armor Class granted when skirmishing. For example, a 4th-level scout/1st-level ranger would deal an extra 2d6 points of damage and gain a +1 competence bonus to AC when skirmishing, as if she were a 5th-level scout.
Your ranger and scout levels also stack for the purpose of determining when you select additional favored enemies, as well as the total bonus granted against your favored enemies. For example, a 4th-level scout/1st-level ranger would have two favored enemies and could allocate an extra +2 bonus against one of those favored enemies, as if she were a 5th-level ranger.
In addition, your skirmish extra damage applies against any creature you have selected as a favored enemy, even if it is normally immune to extra damage from critical hits or skirmish attacks.

[Dasrak]

There are some specific feats that help specific class features. Accomplished Sneak Attacker for sneak attacks and Boon Companion for animal companions coming to mind. The Prestigious Spellcaster feat gives you one extra level of spellcasting progression (not caster level, but actual treats your spellcasting class as one level higher) but only works with some prestige classes. It'd actually be nice to get a list of these collected in one place, since they're exceedingly useful for multiclass characters.