With a couple of exceptions, I've been working with the same basic palate of glazes for nigh on to 40 years here in NH. Instead of being constraining, I find it gives me a huge range of possibilities and sets some "structure" to the work. The decision to do this this way was very conscious and done a long time ago. Working with the same glazes a long time allows me to "know" them pretty well. The palate itself reflects the aesthetic that I am striving to produce.
Like Mark mentioned above... if someone asked me to do a new piece for them that is similar in glaze to something that they bought from me 30 years ago... I could hit that pretty closely.
Matching clay body is the far more difficult one.... because the raw materials for the clay bodies I used 30 and 40 years ago are (sadly) gone, gone, gone. I sorely miss real Jordan Stoneware clay, PBX Fireclay, Pine Lake Fireclay, and more recently the REAL (old) A.P.Green Dry-Milled Fireclay.
Glazes................. An iron saturate tenmoku. An iron red "kaki" (persimmon). A "runny" wood ash grey-green that is from local materials. An American Shino recipe that I developed. An Oribe style green. A chun-like opal blue. A synthetic nuka (rice HUSK ash type). A real nuka (recipe I got from Hamada) for special pieces (mainly tea wares and sake wares). A Karatsu-like semi-gloss gray that takes iron brushwork well.
Add to this above the possibilities of yakishime (unglazed) natural ash glaze from woodfire, and also the impacts of fly ash WITH the above glazes.
Also overglaze enamels in red, green, yellow, teal blue, lavender, black, and white.
Also gold luster in burnish gold and bright gold.
Just last year I started to experiment with a combination of two cone 10 reduction glazes that we have been using at the college for a good while that I kind of like together. That will be the first addition in a LONG time. That combo is Rhodes Black (a semi-gloss opaque black combined with Burton's Yellow (a semi-matte high calcium iron yellow) then combined with some blood red overglaze enamel. I only have a couple of years on limited testing with it so far..... but I think it will likely "stick". I had one piece with this combo on it in my recent solo exhibition.