A root in Quenya Notes (QN) from 1957 glossed “solid, tangible, firm” with derivative Q. ronda “solid, firm” (PE17/183). It had a couple variants: √GRON > S. grond “solid, tangible, firm”, also the name of Melkor’s hammer, as well as √SRON > Q. hrón/S. rhû “matter” and Q. hrondo/S. rhond “body”. The root √SRON appeared again with the gloss “flesh, substance, matter” in etymological notes associated with the essay Of Death and the Severance of Fëa and Hrondo from the late 1950s, along with both Q. hrón “matter” and Q. hrondo “physical body” (MR/231 note #26). However, in the title of this essay hrondo was revised to Q. hröa (MR/217), elsewhere derived from primitive ✶srawā (MR/350); see the entry on √SRAW for further discussion (MR/330).
Regarding S. grond: in The Etymologies of the 1930s this word was derived instead from the unglossed root ᴹ√RUD, which had derivatives ᴹQ. runda “rough piece of wood” and ON. runda > N. grond “club” (Ety/RUD); it also had strengthened variant ᴹ√G-RUD (EtyAC/G-RUD).
Neo-Eldarin: Despite the change of Q. hrondo >> Q. hröa, I think √SRON might be retained in the more limited sense “matter” rather than “flesh”, along with related root √(G)RON “solid” from 1957. As for ᴹ√RUD, it might also be retained, with S. grond “solid; club” being a blending of ᴹ√RUD and √(G)RON.
In Quenya Notes (QN) from 1957, Tolkien gave √TAN “indicate, show” as the basis for Q. tanna “sign, token” (PE17/186) and in notes from the late 1950s Tolkien gave the verbal root √tana “show, indicate” (MR/385). Possible earlier hints of this root can be seem in the first and second versions of Tengwesta Qenderinwa where Tolkien gave √TAN as an extension of demonstrative √TA (PE18/33, 60, 84, 95), but those references were unglossed and may simply have been illustrations of principles of root formation. The use of √TAN = “indicate” would have conflicted with √TAN “make, fashion, construct” (Ety/TAN; PE17/96, 106), but in 1968 or 69 Tolkien changed {√TAN >>} √TAM “construct” (PE17/107); see that entry for details.