The only pens I use are fountain and dip pens (I despise biros), and my pens range from new Jinhao, Hongdian, Lamy, Pilot, Kaweco, Namiki, Twsbi, Visconti, and Montblanc pens, to vintage pens like Sheaffer, Esterbrook, Pelikan, and a few others.
I tend to stick to specific ink colours...black, dark grey, intense deep blue, deep crimson/dark red, and sepia....and I collect far more than I can use.
I also collect and use mechanical pencils and standard pencils, of which I have several dozen, some new, some vintage. For mechanical pencils, I tend to prefer 0.5 and 0.3, and my favourite brands are R0tring, Pentel, and Muji for mechanicals, and probably Blackwing and Mitsubishi for standards.