I found a reference to three Swiss absinthe brands from the 1850-60s.

These brands and descriptions can be found in British & foreign spirits: their history, manufacture, properties, etc. By Charles Tovey
Published in 1864.

Gillard, Elise, and Co.— Absinthe, green. Extremely delicate.; character good.
August Lueba.— Absinthe and Gentian Water. Excellence of character.
Bosselet-Dubied.— Kirschwasser and Absinthe. General excellence.

Seems that the fine people of San Francisco enjoyed their pre-ban absinthe.

Drinking In Big Cities
Varies In Method
Washington Post: Sunday, August 6, 1905

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.

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

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

Generic label. Volume listed indicates for Anglo market.

Generic label. Volume listed indicates for Anglo market.

The glass seal. Slightly crude.

The glass seal. Slightly crude.

The following is an article from 1912 that has a few historical gems (in terms of absinthe). It makes note of four absinthe distillers in the USA and shows how popular absinthe was in New York City at the time. My research suggests there were more than four absinthe producers prior to 1911 but to date, I've found only three brands names.

.....

PLENTY OF ABSINTHE.
But Only for New Yorkers, in Which State It Is Made.

From: New York Herald 1912

The following is a from a book written by Lewis Ford called The variety book containing life sketches and reminiscences. Written in 1892. It was in the personal library of the family that made Butterfly Absinthe in Massachusetts.