It used to be possible to create Autonomous Vassals for everyone.

Like Marches those do not have the +50% development cost penalty of normal vassals.

Unlike Marches they still pay some taxes.

I do not mind e.g. keeping the Trolls as Marches when playing Vaengheim - all that arctic terrain alone will mean they never get the income to make me want to take even a little away from them.

But e.g. Hytiranyalen is a tag focused on economy. If I want them to stick around, what options do I have to actually make use of their capabilities, now that I can no longer turn them into Autonomous Vassals?

Unlike Obrtroll and Digovetha they have a great total of 0 military ideas and they also do not have Trolls or Ogres - or Gnolls, several tags of which can be easily March-ed just a bit to the south.

Ayarallen's mission tree specifically allows us to decide whether to keep them or annex them and I always start to feel down when painting large areas of the map - feels like I am turning it into a dead wasteland.

Being able to create Autonomous Vassals as everyone, not just plot-enabled big-brain special snowflake tags, was one of the high points of Anbennar for me, personally, even before all the setting and additional mechanics.

I liked even that they would sometimes start a stupid war or two - closer to CK2 vassals, another element that keeps some life in the game even in places already subjugated.

... Of course there are a number of tags in Anbennar, which get their own special subject types, e.g. Satrapies also do not get a development cost penalty.
But... what about everyone else?

What options are there? Does any of the idea groups or policies or government reforms unlock a generally-accessible way to establish useful non-March subjects?