Words we already knew

EAR	EGO	EMU	ERG
EAT	EKE	END	ERR
EBB	ELF	EON	EVE
EEL	ELK	ERA	EWE
EGG	ELM	ERE	EYE

Words we already knew because they are plurals of a two-letter word

EAS#	EFS	ELS	ENS
EDS	EHS#	EMS	ERS
EEN#

Special shout-out to EEN, taking an old-styled plural there, just to keep us interested.

The return of mouth sounds!

EEK	when scared
EEW	when disgusted
EFF	when angry, but not angry enough to actually swear
ERM#	when uncertain

Letters

EDH ETH	The Old English letter representing the sound usually written in English as “th” (lower-case ð, upper-case Ð)
ESS	The letter S
ETA	The Greek letter E (upper-case Η lower-case η)
ENG	The glyph ŋ, used in phonetics to represent the sound usually written in English as “ng”, but which never caught on as a letter. Not to be confused with a lower-case ETA. Also AGMA (but not engma)

Abbreviations

ECO	= ecology. A noun. I would have assumed this was a contraction of “ecologically”, but apparently not, and it takes an S.
EMO	= emotional. The music genre.

More actual French

EAU	water. As, presumably, in eau de cologne.

Animals

EFT	originally any small lizard, now mostly used (inasmuch as it’s used at all) to refer to newts
ELT#	a young sow, also YELT#
ERN	a sea eagle, or, poetically and historically, any eagle. Also ERNE. Now chiefly seen in American-style crosswords.
EWT#	a small salamander, also NEWT. Famously one of those words that migrated from being “an ewt” to “a newt”.

Regional, Dialect, and Obsolete

EAN#	(of a EWE) to give birth to a lamb
ECH# EIK#	to augment, as in EKE, also ECHE, EECH, ICH
ECU	an old French coin. The ECU, European Currency Unit was named with the coin in mind, but is still an acronym.
ELD	old age. Hence elder, elderly, Eldar
ELL	a measure of length. As with all such ancient measures, not well-standardised. The English ell was equivalent to 45 inches, the Scottish to 37.2 inches, the Flemish to 27 inches. The same “el” as in “elbow” and “ulna”, because the word derives from words for arm, the measure being notionally the length of an arm, or some portion of it.
EME	an uncle. Recorded earlier than “uncle”, but not since the 19th century
ENE#	variant of EVEN as in “evening” (poetic)
ERF#	South African word for ‘a garden plot, usually containing about half-an-acre’ (plural ERVEN). From a Dutch root meaning “inheritance”, as found in “orphan”, not a eye-dialect spelling of “earth”
ERK#	an aircraftsman. 1920s-1940s. A 1944 quote derives it: “a shortened pronunciation of the italicised letters in air mechanic (perhaps in the form of ‘air mech’)… Some airmen less convincingly maintain that it comes from ‘lower-deck hand’.”. However, there is an earlier citation from 1925:  “Erk, a rating. (Navy). Lower deck colloquialism for any ‘rank’ not that of an officer”.  Although military jargon is the most productive way acronyms become words, it’s still less common than supposed. I would be unsurprised if this originated as a variant of OIK.
EST	An alternative philosophy and technique (Erhard Seminars Training, run in the 1970s-1980s) intended to raise self-awareness and ‘human potential’, involving philosophical and psychological means, including motivational theories from the business world. More fossilised woo. Woo hoo.
EUK# EWK#	Scots and northern English dialect. To itch. Also YUKE, YOUK
EVO#	Australian slang for evening. Comes after AVO
EXO#	Australian slang for excellent. Not “executive officer”, does not take an S.

Back to some stand-out nonsense here. Editors, please remove:

• EST – an acronym and obsolete
• ECH, EIK, EUK, EWK – words from before the invention of spelling

ERK maybe gets a pass for another couple of decades, but we need some statute of limitations of temporally-localised slang like this, and “lifetime of speakers for whom this is idiomatic” seems like a reasonable one. I can imagine EMO and EEW being scorned as fossils within a few decades too, and letting things rotate out seems preferable to a lexicon forever increasing in density of obsolete slang.