Triparic Prepositions

English	Triparic
about (concerning)	re
above, over	ober
after	post
against	contra
almost	pres
among, between	enter
at	an
by (agent, doer)	bä
by (means of)	per
during	dum
except	savŏs
for	fir
from	von
in	en
instead	anplåx
into	en zu
like	vi
near	næ
of (possession/association)	o
on	sur
out of, out from	ŏs von
outside (of)	ŏs
since	sæt
than	que
through	durc
to	zu
under	sob
until	bis
with (accompanying)	wik
without	sen

Shawn proposals

English	Triparic
across	acrøz
along	alang
around	arŏnd
because of
before	ante
behind	hinder
beside	nast (this is from Dutch naast, "next to, beside")
beyond	preter

Source discussion

English	German	Latin	Esperanto	French	Classic Tri
across	über, quer	trans	trans	de l'autre côté de	—
along	entlang, längs	—	laŭ	le long de	—
around	um	circum	ĉirkaŭ	autour de	—
because of	wegen, vor	ob	pro	à cause de	—
before	vor	ante	antaŭ	avant	för
behind	hinter	pone	malantaŭ	derrière	—
beyond	jenseits	ultra, praeter, extra, trans	preter	au-delà de	—