I've been doing some research into absinthe imported to the USA prior to the ban. I found a few I never heard of. Please find the running list below. If you have any info on Richard and Muller or Yersin & LeCoultre, please let me know.

I started a discussion here if you have any comments:

Our FaceBook Discussion Page

Pre-Ban Absinthe Imported Into the USA (running list)

Richard and Muller (Swiss)
Source: The Daily True Delta 1859 NOLA

Pernod (Green and White)
(well documented)

Edouard Pernod
Source(s):
(1) Atlanta Constitution. November 21, 1897
(2) NOLA 1906 City Directory P. 745. The Ned Palfrey Co. Sole Agent

C.F. Berger
Source: NOLA City Directory 1881 C.F. Berger sold by E.J. Hart & Co. 73-79 Tchoupitolas St.

A. Mortiers Gravers Superior Absinthe (Swiss)
"A. Mortiers Gravers, canton de Neuchatel, Suisse"
Source(s):
(1 )The Daily True Delta 12-21-1896 NOLA
For Sale by George Palmer
149 Common Street

(2) New Orleans Commercial Bulletin. December 8, 1846 No. 275

(3) L'Abeille. NOLA October 3, 1829 Vol 3.