All consonants (and zero) occur as onsets of word-initial syllables except /z/, /ñ/ and /y/. All consonants occur, without restriction, as medial syllable onsets.
Moderately complex onsets:C1=obstruent
s + C: This is very rare; C1=s; C2=vl. stop; one example of /fs/
Complex onsets: This is very rare, mostly in Dutch loans. Only /str/ and /frv/ are known word-initially, /skr/ and, depending on analysis, /drv/ medially.
Source: Smith 1977: 146
Source: Smith 1977: 45
Source: Smith 1977: 45-51
Source: Smith 1977: 45