Apart from what is listed on the original Emma pattern, you'll need:
Fabric, for facings/button placket. Requirement in width: 50 cm. Length: 80 cm for blouse; 100 cm for short dress; 120 cm for calf-length dress. You can use the same fabric as on your blouse/dress. If you want knit fabrics, look for tencel jersey, viscose jersey, bambu jersey or modal jersey. If you want woven fabric, looks for cotton or linen, for example cotton lawn or batiste. Or why not viscose, crepe, chiffong or georgette. Remember that a very light-weight, slippery fabric can be more challenging to sew.
Fusible interfacing. The requirement is the same as for fabric (see above). The purpose of the interfacing is to stabilize the neckline and button placket. If your fabric is knit, use an interfacing with a little bit of stretch (10-30%). Most important is to choose an interfacing that is as light, or lighter, than the fabric.
Buttons, up to 10-11 buttons for a calf-length dress, and approx. 6-7 buttons for a blouse. Remember not to choose too big/heavy buttons if your fabric is light, they will weigh down the dress. If your fabric is light - choose small and light buttons (approx. 10-15 mm). If you don’t want to sew buttonholes you can choose snap buttons.