Generika
Here are some suggestions for Anglo-Saxon generic leaders and army names - suitable for Kent, Wessex, East Anglia, Mercia, Northumbria.
Armies: Heorthgeneatas [hearth-companions], Dryhtnes Gesithas [lord's comrades], Micel Here [great army], Lytel Here [lesser army], Sibbgedryht [company], Cyninges Werod [king's comitatus], Aethelinges Hird [aetheling's retainers], Westsexena Fyrd, Myrcna Fyrd, Nordhanhymbrisc Fyrd, Cantwarena Fyrd, East Englisc Fyrd, Eastsexena Fyrd, Cilternsaetna Fyrd, Suthsexena Fyrd, Mide Englisc Fyrd, Westerna Fyrd
Leaders: Wulfstan, Coenhelm, Cwichelm, Beaduheard, Cuthred, Eadmund, Aethelbald, Wulfnoth, Saeberht, Sigeberht, Aethelberht, Nothhelm, Wilfrede, Ingeld, Swaefheard, Wynfrith, Ceolfrith, Aethelheard, Cynewulf, Cynegils, Beorhtric, Sigeric, Osrede, Oswulf, Oswald, Osric, Osberht, Oswine, Godric, Godrede, Guthmund, Eanberht, Eanrede, Uhtred, Aethelweard, Hereweard, Heremod, Beorhthelm, Ealfwold, Hun, Burhrede, Cenwulf, Eata, Basa, Wiglaf, Wocca, Eadrede, Aethelstan, Eadgar, Eadweard, Aethelrede, Aelle, Wihtrede, Eadwine, Odda, Frithuwald, Lilla, Wulfrun, Willeuhad, Aethelwulf, Aelfrede
I'll have to speak with m'learned friends to get the equivalent for Celtic nations, though here's some generic 'British' names:
Cadoc, Petroc, Iago, Idwal, Rhodri, Ceretic, Cadell, Hywel, Macsen, Coel, Rhydderch, Merfyn, Cynfyn, Bleddyn, Rhiwallon, Anarawd, Owain, Maredudd, Condidan, Custennin, Dumhgert, Llywelyn, Gruffydd, Beli, Rhun, Artgal, Llywarch, Peredur, Gereint, Erbin, Gwyrthefyr
Picts...
Dubh, Gartnait, Drust, Talorgan, Nechtan, Bruidhe, Bridei, Bili, Albin, Cinaid, Onuist, Maelchon, Cinioch, Constantin, Oengus etc
and Bretons...
Nominoe, Salomon, Conan, Alan, Erispoe, Dinan etc etc
require separate lists I think, but the above will suffice for S'clyde, Gododdin, Rheged, Gwynedd, Dyfnain, Calchvynydd and Pengwern.