R6RS greatly extends the list of character names,
as well as allowing #\xNN numeric escapes for characters.
Do we allow any or all of these names?
What is extremely odd here is that the lists of names in R5RS 6.3.4 and R6RS 4.2.6 are both introduced by "For example:", so they are not really normative! What is normative is the BNF grammars in R5RS 7.1.1 and R6RS 4.2.1, and neither of them define the term <character name> at all, so evidently implementations can use whatever names they like.
So I tried #\nul #\alarm #\backspace #\tab #\linefeed #\newline #\vtab #\page #\return #\esc #\space #\delete on my usual list of Schemes.
Gambit, Chicken, Bigloo, Kawa, Chez, Ikarus, Larceny, SSCM, and SXM like them all.
PLT doesn't like alarm, esc.
MIT doesn't like alarm, vtab.
SCM and Guile don't like alarm, linefeed, vtab, delete.
Gauche doesn't like alarm, backspace, linefeed, vtab.
VSCM doesn't like nul, linefeed, page, delete.
SISC doesn't like alarm, linefeed, vtab, esc, delete.
s7 doesn't like alarm, backspace, vtab, page, esc, delete.
Chibi doesn't like nul, alarm, backspace, linefeed, vtab, page, esc, delete.
Bigloo, Scheme48/scsh, Scheme 9 don't like nul, alarm, backspace, tab, linefeed, vtab, page, return, esc, delete.
I recommend we require the whole set.
The WG voted to accept numeric escapes plus a list of character names to be voted on later.
Use the list of names decided in #84.