Another site:
AllTop 200 most popular tests to learn English...
1) Test de niveau anglais (webmaster) 6 781 995
2) Placement test : grammar for beginners (anonyme) 5 998 484
3) A/AN (webmaster) 5 369 172
4) Auxiliary BE (webmaster) 3 226 176
5) Present continuous (webmaster) 3 001 829
6) Present simple (webmaster) 2 921 674
7) Present simple (webmaster) 2 599 720
8) Present continuous (webmaster) 2 438 565
9) Adjectives (webmaster) 2 094 807
10) A/an (anonyme) 2 017 517
11) Present perfect simple (webmaster) 1 647 709
12) Preterite (webmaster) 1 633 668
13) Vocabulary - Placement test (bridg) 1 620 345
14) Preterite (webmaster) 1 451 022
15) Short placement test (webmaster) 1 444 544
16) To be (bridg) 1 407 432
17) What time is it? (webmaster) 1 350 588
18) Present perfect (webmaster) 1 349 693
19) The alphabet in English (webmaster) 1 322 254
20) Adjectives (anonyme) 1 217 080
21) What time is it? (webmaster) 1 210 537
22) Numbers (webmaster) 1 189 289
23) 'A' ou 'An' (anonyme) 1 177 106
24) Two presents: present continuous, present simple (webmaster) 1 150 799
25) To be (bridg) 1 146 531
26) Comparatives / Superlatives (webmaster) 1 107 856
27) Numbers (webmaster) 1 071 824
28) CAN / MUST (webmaster) 1 059 517
29) THE/ A / AN / nothing (webmaster) 1 035 570
30) Comparatives (webmaster) 1 008 082
31) Family life (bridg) 1 001 833
32) Numbers > 100 (webmaster) 987 263
33) Future (going to/will/present continuous) (anonyme) 965 554
34) Plural (webmaster) 956 668
35) Superlatives (webmaster) 876 104
36) Adjectives (anonyme) 875 630
37) Simple present (bridg) 854 989
38) Spelled words N°1 (bridg) 851 052
39) Placement test beginners: Check your spelling (anonyme) 830 573
40) Introducing oneself (webmaster) 827 736
41) Adverbs of frequency (anonyme) 818 804
42) Family (bridg) 785 552
43) General test-End of high school / Beginning of university (webmaster) 783 674
44) Present simple (anonyme) 782 692
45) Frequency adverbs (webmaster) 778 440
46) Present BE + Ving (bridg) 766 400
47) Passive form (anonyme) 727 441
48) Genitive (webmaster) 724 295
49) Family tree (anonyme) 720 082
50) Preterite: simple or continuous? (webmaster) 717 802
51) Placement test (beginners) (lili73) 702 144
52) Past simple or present perfect (anonyme) 696 283
53) Future (webmaster) 676 530
54) Present perfect simple (bridg) 663 338
55) 2 Preterites (webmaster) 663 237
56) Preterite (webmaster) 622 014
57) List of 200 irregular verbs and audio (bridg) 617 006
58) Modals (webmaster) 613 289
59) Spelled words N°2 (bridg) 609 880
60) Modals (webmaster) 607 137
61) Height (webmaster) 606 804
62) Articles a / an / the (anonyme) 596 779
63) Plural forms (bridg) 578 276
64) Nationalities (webmaster) 574 811
65) Past continuous / Past simple (anonyme) 568 380
66) Irregular plurals (bridg) 554 347
67) Two presents: simple and continuous (webmaster) 550 298
68) Preterite (bridg) 549 724
69) Superlatives (frapedur) 540 908
70) Vocabulary: greeting people (here4u) 536 555
71) Give your opinion (bridg) 532 615
72) Adverbs of Frequency (bridg) 517 483
73) Present simple or continuous (anonyme) 512 766
74) Present perfect / preterite ? (anonyme) 511 411
75) Possessive case (anonyme) 481 217
76) Countries & nationalities (bridg) 474 064
77) Past tenses (bridg) 471 757
78) 'The' or nothing? (webmaster) 471 672
79) Introducing oneself (easy) (webmaster) 471 111
80) Passive voice (webmaster) 464 368
81) Present Simple vs. Past Simple (anonyme) 459 483
82) Questions : how to ask them (anonyme) 448 933
83) General Test II / End of high school / Beginning of universi (webmaster) 446 629
84) IN, ON, AT or TO? (webmaster) 445 978
85) Relative pronouns (webmaster) 445 431
86) Comparative of superiority (anonyme) 439 912
87) How to pronounce the final -ED? (past simple) (webmaster) 438 958
88) Relative clauses (webmaster) 423 932
89) Sounds: [h] (webmaster) 419 858
90) Comparative (anonyme) 414 884
91) A/an/Ø (bridg) 399 404
92) Past simple (anonyme) 399 202
93) Future simple (anonyme) 397 267
94) This / That / These / Those (webmaster) 392 946
95) Conditional (webmaster) 392 319
96) Passive voice (anonyme) 391 316
97) Comparing (webmaster) 388 388
98) Can / could/ may/ might (woodyrun) 380 280
99) Present perfect or past tense (anonyme) 378 579
100) Much, many, little and few (felin) 373 864
101) Personal pronouns (anonyme) 371 535
102) Preterite continuous (BE + -ING) (webmaster) 370 385
103) Genitive case (bridg) 368 669
104) Some, any, no, enough, too/too much/too many (webmaster) 368 531
105) Confusing words - Placement test (bridg) 364 856
106) Irregular verbs (webmaster) 364 222
107) Numbers from 1 to 10 (anonyme) 361 865
108) Past perfect simple, past perfect continuous (anonyme) 361 134
109) Present continuous or present simple (webmaster) 359 937
110) Present perfect or preterite? (anonyme) 358 107
111) Simple Past : regular verbs (anonyme) 354 077
112) Comparative Adjectives (bridg) 352 597
113) Who, Whom, Which, or Whose? (anonyme) 349 452
114) Past simple (video) (anonyme) 349 102
115) Past simple or past continuous (anonyme) 344 508
116) While / When (anonyme) 340 069
117) What time is it? (webmaster) 338 393
118) Modals (tinou) 336 948
119) Modal: may/might (anonyme) 334 513
120) Cardinal and ordinal numbers (anonyme) 329 045
121) The superlative (anonyme) 326 978
122) Possessive adjectives and pronouns (woodyrun) 324 801
123) How to talk about the weather (lili73) 320 932
124) Since and for (anonyme) 319 389
125) Flags (webmaster) 317 904
126) Irregular verbs (bridg) 316 459
127) Pronouns (woodyrun) 314 826
128) Prepositions - in, on, at (anonyme) 314 423
129) Tenses (anonyme) 312 637
130) Placement test 3 (webmaster) 310 813
131) Order of adjectives (webmaster) 306 895
132) Could/Couldn't (laure95) 306 429
133) Comparative (anonyme) 305 040
134) Adjectives and prepositions (anonyme) 304 406
135) Agreement Tags (webmaster) 304 339
136) Asking questions (webmaster) 303 524
137) Present perfect OR simple past? (bridg) 298 696
138) Questions in the past tense (anonyme) 298 032
139) Uncountable nouns (webmaster) 296 281
140) Superlative Adjectives (bridg) 296 175
141) Object pronouns (bridg) 295 744
142) Placement test 1 (anonyme) 293 133
143) Passive form (anonyme) 292 620
144) Present simple (anonyme) 291 771
145) Can/Must/Should (laure95) 290 690
146) Prefer/rather (bridg) 289 851
147) Past perfect (lili73) 289 522
148) Must or Have to? (woodyrun) 288 042
149) The/an/nothing (bridg) 285 609
150) To be (anonyme) 283 588
151) Can and can't (laure95) 282 333
152) Vocabulary: asking and answering (here4u) 280 485
153) Modal verbs (bridg) 277 539
154) Some / Any / no... (bridg) 274 539
155) Days of the week (bridg) 269 163
156) So / neither (anonyme) 264 528
157) Past simple (video) (anonyme) 263 979
158) Present continuous (chnawa) 261 247
159) Used to (bridg) 260 513
160) Should / must (anonyme) 260 043
161) Past tense (anonyme) 259 605
162) Vocabulary: on the phone (here4u) 258 799
163) Find out a quantity (webmaster) 258 700
164) Articles : a / an / the / Ø (anonyme) 257 861
165) Superlative + and adjective (anonyme) 257 631
166) Comparative and superlative (anonyme) 256 376
167) Numbers 1/100 (anonyme) 253 847
168) Modal can (video) (anonyme) 253 224
169) Comparatives (anonyme) 249 885
170) Relatives pronouns (who, which, that...) (anonyme) 247 874
171) A few, a little, few, little (anonyme) 246 075
172) Vocabulary: at the restaurant (here4u) 245 696
173) Would rather / would prefer to (anonyme) 244 651
174) Present continuous and the Going to form (anonyme) 243 085
175) Should/ have to/ must (anonyme) 240 689
176) Have something done (anonyme) 240 050
177) Used to/would (woodyrun) 238 018
178) The past (webmaster) 237 954
179) Future continuous and future perfect. (felin) 237 918
180) How to ask a question in English (bridg) 235 846
181) Pluperfect (webmaster) 234 298
182) I wish, if only (felin) 234 273
183) Countable or Uncountable? (webmaster) 233 570
184) Some / any (younes91) 233 492
185) Should / shouldn't (anonyme) 231 811
186) Present simple or continuous (bridg) 230 812
187) Adjectives - ing and ed (felin) 229 357
188) Hypothesis (webmaster) 228 488
189) Auxiliary BE (anonyme) 226 564
190) Articles a/an/the/0 (bridg) 226 410
191) Must or mustn't (laure95) 226 302
192) Article The or nothing (anonyme) 226 194
193) Present perfect with Ever - never - (anonyme) 226 021
194) Present continuous OR Present simple? (bridg) 225 637
195) Simple Preterite OR Preterite (BE+ing) (webmaster) 223 059
196) To / in order to / so as to / so that (irish21) 220 821
197) Comparison (komiks) 220 104
198) Present perfect (bridg) 219 683
199) What time is it ? (anonyme) 217 814
200) Indirect speech (bridg) 217 278
