I'm Belgian. :-) And they're few 100% Belgian names. Probaly because we have 3 official languages (Dutch, French, German), we have a wide variety of names: French, Dutch, Scandinavien, English, Slavic, etc. . You won't find a lot of Scandinavian names in the French part of Belgium because some of them have souds which are known in Dutch but not in French.
Ingrid for example is indeed a quite common name in the Flemish part, but it's regarded as a bit old fashioned cause I don't think you'll find an Ingrid below the age of 40/45 nowadays. Nevertheless, there's nothing wrong with the name. :-)
Inge and Ilse are also common in that same region but most women with those names are also in their 40's now. And I think it's very hard to pronounce those names in English.
Other Scandinavian names you'll hear around here: Gitte, Jytte, Marit, Astrid, Ine, Berit, Merit, Jente, Yorunn, Dagmar, Ebba, Anneli, Inga, Mette, Ragna, Randi, Jelle, Mille, Kari, Karen, Kirsten, Kerstin, Elin, Gudrün, Birgit, Birte, Bente, Britt, Britta, Malin, Sigrid, Siggi, Agnes, Ania/Anja (also Russian), Annika, Ilva, Thyrza, Freya, Gitta, Ginthe, Karin, Lisbeth, Rhune, Runa, Stina, Svenja, Svea, Thyra Liv, Linn (Scandinavian form of Lynn)... Names like that have something in common with Dutch names (from The Netherlands) and as Dutch is the official language in Flanders, you hear them quite often: Maaike, Femke, Famke, Silke, Marijke, Renske, Wencke, Elke, Saartje, Kaatje, Kaat, Dieuwke, Hanne, Hanneleen, Hannelien, Liselotte, Liselore, Annelies, Annelien.
Old names of Low Lands literature are Isolde and Soetkin.
Also Cato/Kato (actually a French shortening of Catharina) is pretty common and a name you only here in Belgium nowadays and less common in the Netherlands. Other names which can be called 'Belgian' (or actually Flemish) because their pronounciation is quite hard for both French and English speaking people are: Nore, Febe, Tinne, Janne, Jante, Jinte, Sien, Noor, Jenne, Jelte, Siene, Stien, Sanne, Lisse, Lize, Gudrün, Nette, Nelle, Ans, Nele, Els, Mieke, Marieke, Fien, etc. Charlotte is a very popular name here and most Charlotte's I know have siblings with another French or classical name but that's not what you're looking for, is it? And oh, I know an Icelandic girl who'se name is Bryndis. I quite like that name. :-)