The nut inside the dowel is called a threaded insert. Also known as a Captive nut in some places. https://www.ebay.com/itm/20Pcs-Lot-Carbon-Steel-Hex-Socket-Drive-Insert-Nuts-Threaded-For-Wood-Furniture/123193517035?_trkparms=aid%3D888007%26algo%3DDISC.MBE%26ao%3D1%26asc%3D20131227121020%26meid%3Dc6b1f1d4a55d43b2a05ae49f8c5be563%26pid%3D100009%26rk%3D1%26rkt%3D1%26sd%3D252289075106%26itm%3D123193517035&_trksid=p2047675.c100009.m1982
The bolts are called Self Tapping Hanger Bolts. You select the thread size to match your captive nut inserts. https://www.ebay.com/itm/M4x25mm-Carbon-Steel-Zinc-Plated-Self-Tapping-Hanger-Bolt-20pcs/352201912476?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3Df9f1642ad93341b1adf5a26fcef40c21%26pid%3D100005%26rk%3D2%26rkt%3D2%26sd%3D352201923785%26itm%3D352201912476&_trksid=p2047675.c100005.m1851
The last bits are called Drywall plugs or anchors, also known as Rawlplugs in some places.