I have a reliable oat biscuit recipe which gets modified a lot to include various flavours:
- cinnamon or mixed spice
- ginger (ground and finely-diced stem)
- apple
- raisin
- chocolate (bulk and/or chip)
- lemon/orange/lime zest
None of them are good dunkers mind and, oddly, the ginger version tends to come out more 'robust'.
For packeted goods, I'm pretty good on any and all of them, from the lowly Rich Tea, through the Nice, Arrowroot, Malted Milk, Ginger Nut to the Hob Nob, Abbey Crunch, Bourbon, Custard Cream and such rare delights as the Lemon Puff and the daddy of them all, the plain chocolate digestive (McVitie's only though). Never came across a biscuit I wouldn't eat.