You can buy just about everything in the handicrafts line in Madagascar. Most typical of the country are wood carvings, raffia work (in amazing variety), crocheted and embroidered table-cloths and clothes, semi-precious stones (the solitaire sets are typical and most attractive), leather goods, carved zebu horn, Antaimoro paper (with embedded dried flower), and so on. The choice is almost limitless, and it cas be seen in the artisans' market of Andravoahangy or CENAM.
Other local products which make good presents are vanilla pods (although strictly speaking you are limited to 100 g), pepper corns, saffron and other spices and honey. Do not buy products from endangered species, endemic plants fossils and any genuine article of funerary art. The luggage weight limit when leaving Madagascar is 20 kg or 30 kg if you are going non-stop to Paris which manages to count as a "national" flight. Bear this in mind when doing your shopping.