First of all, these are all easy targets. They´re not in NATO, have little military capabilities, and are close neighbors. If Putins wants to, he can do it without too much extra risk and without needing too many troops. Should he win in Ukraine or Trump get reelected, or he needs some kind of "success" or distraction, he might be tempted to satisfy his imperialistic appetite in one or more of these. These are all but Armenia MUCH more likely than the baltic states IMO.
1) Moldova
They´ve got serious trouble over Transnistria (link 1), plus russian troops are already guarding the military depot (link 4). Putin might decide to distract from other things by simply taking over the country (one of those lovely "provocations", and he has a "reason). Easiest target, most trouble already.
2) Armenia
Russia seems to withdraw it´s peace troops (incredible, but there this might indeed have been the intention; link 5) from Armenia. Why should they come back to occupy the country? Very unlikely.
3) Georgia
They´ve done this before (2008), and currently there are large anti-russian protests (link 2). Strong candidate.
4) Kazakhstan
With the flood of the century currently going on (the news are full of this) and Kazachstan depending on Russia economically as well (link 3), I don´t see an immediate reason to invade the country. OTOH not everone there is agreeing with Russia vs. Ukraine, and Russia being imperialistic as it is, Kazakhstan might be an easy "success" for Putin, so there is a little threat as well.
https://www.spiegel.de/ausland/transnistrien-darum-geht-es-in-dem-konflikt-zwischen-russland-und-moldau-a-60b16625-82ea-4186-b39d-6777e13fa8ac
https://www.fr.de/politik/massenproteste-georgien-putin-droht-rebellion-nachbarland-gesetz-russland-93017804.html
https://de.wikipedia.org/wiki/Kasachisch-russische_Beziehungen
https://de.wikipedia.org/wiki/Munitionsdepot_Cobasna
https://www.n-tv.de/politik/Russland-zieht-Soldaten-aus-Berg-Karabach-ab-article24879142.html
This will most probably either happen on Saturday, 20 April in the House (no serious problems to be expected in the Senate), or not before 1 May. To exceed $10 billion should be no problem.
Ready to cut my forecast in half or go even lower, if it doesn´t happen on Saturday.
https://www.n-tv.de/politik/US-Kongress-stimmt-noch-diese-Woche-ueber-Ukraine-Hilfen-ab-article24881549.html