I have identified the following errors / misprints in Goodwin’s Greek Grammar, Goodwin’s Moods and Tenses, and Smyth’s Greek Grammar. The correct readings are highlighted in yellow. Indexer has been silently updated, asterisks being used to show where the errors / misprints occur.

Goodwin's Greek Grammar, Paragraph 1006
Ar. R. 198

Goodwin's Greek Grammar, Paragraph 1357
A. Pe. 912

Goodwin's Greek Grammar, Paragraph 1430
X. A. 6. 4. 9

Goodwin's Greek Grammar, Paragraph 1619
P. Phil. 19 b

Goodwin's Moods and Tenses, Paragraph 28
Thuc. vi. 17 (first reference)

Goodwin's Moods and Tenses, Paragraph 777.1
Id. Crat. 392 C

Smyth's Greek Grammar, Paragraph 1036
S. Ant. 793

Smyth's Greek Grammar, Paragraph 1062
T. 4. 20

Smyth's Greek Grammar, Paragraph 1089
T. 3. 82

Smyth's Greek Grammar, Paragraph 1490
T. 3. 64, 4. 109

Smyth's Greek Grammar, Paragraph 1810
ζ 275

Smyth's Greek Grammar, Paragraph 1939
B 114

Smyth's Greek Grammar, Paragraph 1974
T. 4. 114

Smyth's Greek Grammar, Paragraph 1978 (error 1 of 2)
I. 14. 16

Smyth's Greek Grammar, Paragraph 1978 (error 2 of 2)
T. 4. 20

Smyth's Greek Grammar, Paragraph 2253
ρ 21

Smyth's Greek Grammar, Paragraph 2416
Γ 216

Smyth's Greek Grammar, Paragraph 2421
I. 17. 15

Smyth's Greek Grammar, Paragraph 2483
Π 297

Smyth's Greek Grammar, Paragraph 2515
Ar. Vesp. 212

Smyth's Greek Grammar, Paragraph 2633 b.
T 6. 49

Smyth's Greek Grammar, Paragraph 2689 b.
Ξ 48 (reference unidentified)

Smyth's Greek Grammar, Paragraph 2698 e. N. 2 (2)
I. 14. 52

Smyth's Greek Grammar, Paragraph 2735
7. 35 (second reference)

Smyth's Greek Grammar, Paragraph 2768
Δ 512 (not Β 703)

Smyth's Greek Grammar, Paragraph 2810
X. A. 7. 6. 33 (not P. A. 30 c)

Smyth's Greek Grammar, Paragraph 2879
21. 36 (second reference)

Smyth's Greek Grammar, Paragraph 2886
P. Alc. I 110 d

Smyth's Greek Grammar, Paragraph 2934
P. Alc. I 113 c

Smyth's Greek Grammar, Paragraph 2964
T. 2. 20 (first reference – conjecture)