One could happily spend hours wandering through showrooms which display rolls and rolls of glorious fabrics. Funnily enough I always seem to be drawn to the bearded silks and shimmering organza and the only thing that prevents me from using the more luxurious velvets and damasks is the price. Otherwise I have no limitations.
Many of the fabrics I use are from well known suppliers. However I tend to search around for fabric shops situated in out of town locations which have access to numerous mills who supply them with closeouts and stocks to clear. This way I can find very high quality fabrics at extremely low prices. One has to do one's own research including a dedicated search online which often leads to these treasures.
If you have a difficulty finding some of the specific fabrics you are looking for bear in mind that you can almost always use any fabric which catches your eye. Sometimes it is the fabric found which does the leading and you end up creating an item to fit the fabric. I often do not adhere to the hard and fact rule applied to using a particular fabric. I feel that the most important thing is to get excited about the particular piece of fabric whether it is a brightly coloured patterned or unusual piece of cloth.
I often buy something that is bold enough to catch my eye, and only later find a use for it. Sometime I'll rediscover a fabric at the very bottom of my cupboard which I bought ages ago and never used, and I will instantly be inspired and know just what to make with it. So, it can be worthwhile buying that old piece of lace from a shop, or the odd remnant from a shop who specialise in buying designers surplus stocks. I do this in the hope that one day it will inspire me. Sometimes I find a piece of lining fabric which I use to include wadding, which is a padded, usually synthetic, interlining. I use this extensively to soften an otherwise hard surface such as the pelmet, headboard or the lid of a toy box.
Bukram is a heavy stiffened cloth that is usually made from cotton. This is particularly useful for lining tiebacks and curtain pelmets. Curtain lining is usually sateen, which comes in the instantly recognisable buff or ivory colour. However I often think it is better to find a coloured lining for curtains such as the many glazed chintz, which look good and come in hundreds of colour ways. Or why not think about lining a patterned fabric with another patterned fabric? It's daring and a little expensive, but can look very dramatic and luxurious.