For the Migration Period proper (aka up to VI century)
Any PoD in Europe that changes situation in the I/II centuries can arguably changes how the german (in a geographic meaning, not ethnic) leagues of tribes and people can be done. Particularly the western ones were made of different people tied by circumstence rather than real affinity or parenty.
Furthermore, the presence of germanic people in precise aeras (by exemple, Franks in N-E Gaul) are partially due to the presence of earlier migrants in these regions since the III, more or less forced to live there by Romans after failed raids.
No Hunnic "Empire" could be interesting : as all nomadic empires they absorbed -without assimilating them- many different groups or leagues, delaying their own autonomous migrations partially or more or less completly.
The most "workable "regions seems to me to be 1)Britain 2)Balkans and 3)Spain
1)Britain.
The historical migrants people were many, and quite differents : If the bulk of germans were Saxons, Angles, Frisians, Jutes and Franks are attested as well, and depending on how the west of Roman Empire reacts to first raids or first waves of migrations, some can be added or some people can have eventually the lead.
2)Balkans
Having a weaker ERE can make things really interesting there, ending with a Gothic Greece, a Sarmatic Dacia, etc.
3)Spain
The region is rich, and having more sucessful maritime piracy and raids in the III century could end with at least establishment forced by Romans (as in Gaul) of former raiders. Here, Saxons, Moors, Franks...
The less are Africa and Orient, mostly because crossing Mediterranea without mastering and controlling the sea (not that easy for nomadic people) represents a serious disadvantage.
For the later periods.
Normans : not that easy, if they manage to raid and ravage efficiently the continental shores, they don't have enough forces and possibilities to hold territories without any real local support (the only true establishment, as Normandy, are actually enforced by local rulers).
Still, you can have alt-Normandy in region with loose controls and/or needing to be protected against raids : Gascony, Britanny, Frisia are good possibilities in Western Francia.
Slavs : No Avar Khaganate (that, more or less, used slavic groups on its borders) and a more powerful ERE could lead to a less important slavic presence in Balkans and MittleEuropa (while more present along Baltic)
Arabs/Berbers : Most obvious change. Delay or prevent conquest and you'll have enough changes to fill a TL
Magyars can be "easily" put in different regions, critically with more efficient Eastern Frankish replica : Poland by exemple, is a good choice.