I used a Waterman expert for a long time till a "friend" dropped it and destroyed it. Since then, I bought a Noodlers Ahab. The company had a quirky sense of humour and with a black ink called "heart of darkness", who can resist? I bought it primarily because the nib is flexible and you can use it for pseudo Copperplate and Spencerian scripts (which I use for headings). https://www.amazon.in/Noodlers-Ahab-Flex-Nib-Fountain/dp/B00...
The mechanical pencil I use is a Pentel Graphgear 1000. It's easily the Mercedes Benz of mechanical pencils. Pentel is generally good at this but the Gg 1000 takes it to the next level. It's very well balanced, comfortable to hold and has a few small features that protect the delicate parts quite well. https://www.amazon.in/Pentel-Graphgear-1000-Drafting-Pencil/...