Another site:
AllTop 200 most popular tests to learn English...
1) Test de niveau anglais (webmaster) 6 774 790
2) Placement test : grammar for beginners (lucile83) 5 985 869
3) A/AN (webmaster) 5 361 393
4) Auxiliary BE (webmaster) 3 222 414
5) Present continuous (webmaster) 2 996 822
6) Present simple (webmaster) 2 906 840
7) Present simple (webmaster) 2 595 189
8) Present continuous (webmaster) 2 429 417
9) Adjectives (webmaster) 2 092 439
10) A/an (anonyme) 2 013 209
11) Present perfect simple (webmaster) 1 639 027
12) Preterite (webmaster) 1 621 867
13) Vocabulary - Placement test (bridg) 1 618 268
14) Preterite (webmaster) 1 443 781
15) Short placement test (webmaster) 1 442 647
16) To be (bridg) 1 405 038
17) What time is it? (webmaster) 1 348 031
18) Present perfect (webmaster) 1 342 686
19) The alphabet in English (webmaster) 1 319 975
20) Adjectives (lucile83) 1 214 790
21) What time is it? (webmaster) 1 206 000
22) Numbers (webmaster) 1 187 955
23) 'A' ou 'An' (anonyme) 1 173 849
24) Two presents: present continuous, present simple (webmaster) 1 147 972
25) To be (bridg) 1 144 608
26) Comparatives / Superlatives (webmaster) 1 100 040
27) Numbers (webmaster) 1 069 669
28) CAN / MUST (webmaster) 1 057 767
29) THE/ A / AN / nothing (webmaster) 1 031 560
30) Comparatives (webmaster) 1 006 432
31) Family life (bridg) 999 817
32) Numbers > 100 (webmaster) 985 740
33) Future (going to/will/present continuous) (anonyme) 962 062
34) Plural (webmaster) 954 960
35) Superlatives (webmaster) 874 167
36) Adjectives (anonyme) 873 979
37) Simple present (bridg) 852 892
38) Spelled words N°1 (bridg) 849 373
39) Placement test beginners: Check your spelling (lucile83) 829 701
40) Introducing oneself (webmaster) 826 685
41) Adverbs of frequency (lucile83) 815 856
42) Family (bridg) 783 928
43) General test-End of high school / Beginning of university (webmaster) 782 068
44) Present simple (lucile83) 778 626
45) Frequency adverbs (webmaster) 777 138
46) Present BE + Ving (bridg) 764 012
47) Genitive (webmaster) 722 963
48) Family tree (anonyme) 718 773
49) Passive form (lucile83) 715 815
50) Preterite: simple or continuous? (webmaster) 715 425
51) Placement test (beginners) (lili73) 700 202
52) Past simple or present perfect (lucile83) 692 200
53) Future (webmaster) 675 376
54) 2 Preterites (webmaster) 660 985
55) Present perfect simple (bridg) 658 443
56) Preterite (webmaster) 619 125
57) List of 200 irregular verbs and audio (bridg) 615 250
58) Modals (webmaster) 612 202
59) Spelled words N°2 (bridg) 608 596
60) Height (webmaster) 605 919
61) Modals (webmaster) 603 872
62) Articles a / an / the (lucile83) 596 730
63) Plural forms (bridg) 576 748
64) Nationalities (webmaster) 573 732
65) Past continuous / Past simple (anonyme) 563 931
66) Irregular plurals (bridg) 552 959
67) Two presents: simple and continuous (webmaster) 549 032
68) Preterite (bridg) 548 268
69) Vocabulary: greeting people (here4u) 536 425
70) Superlatives (frapedur) 536 048
71) Give your opinion (bridg) 531 374
72) Adverbs of Frequency (bridg) 516 496
73) Present simple or continuous (lucile83) 509 024
74) Present perfect / preterite ? (anonyme) 507 340
75) Possessive case (anonyme) 480 083
76) Countries & nationalities (bridg) 472 834
77) 'The' or nothing? (webmaster) 470 849
78) Introducing oneself (easy) (webmaster) 470 363
79) Past tenses (bridg) 470 008
80) Passive voice (webmaster) 462 032
81) Present Simple vs. Past Simple (anonyme) 455 534
82) Questions : how to ask them (lucile83) 447 673
83) General Test II / End of high school / Beginning of universi (webmaster) 445 723
84) IN, ON, AT or TO? (webmaster) 444 470
85) Relative pronouns (webmaster) 443 558
86) Comparative of superiority (lucile83) 437 143
87) How to pronounce the final -ED? (past simple) (webmaster) 436 413
88) Relative clauses (webmaster) 422 708
89) Sounds: [h] (webmaster) 419 181
90) Comparative (anonyme) 412 475
91) A/an/Ø (bridg) 397 937
92) Future simple (lucile83) 395 398
93) Past simple (anonyme) 394 628
94) This / That / These / Those (webmaster) 392 144
95) Conditional (webmaster) 391 087
96) Passive voice (anonyme) 389 784
97) Comparing (webmaster) 387 693
98) Can / could/ may/ might (woodyrun) 378 889
99) Present perfect or past tense (anonyme) 376 246
100) Much, many, little and few (felin) 371 606
101) Personal pronouns (anonyme) 371 112
102) Preterite continuous (BE + -ING) (webmaster) 368 034
103) Some, any, no, enough, too/too much/too many (webmaster) 367 816
104) Genitive case (bridg) 367 384
105) Confusing words - Placement test (bridg) 364 366
106) Irregular verbs (webmaster) 363 044
107) Numbers from 1 to 10 (lucile83) 361 200
108) Past perfect simple, past perfect continuous (anonyme) 360 675
109) Present continuous or present simple (webmaster) 359 271
110) Present perfect or preterite? (anonyme) 355 649
111) Simple Past : regular verbs (anonyme) 352 048
112) Comparative Adjectives (bridg) 351 891
113) Who, Whom, Which, or Whose? (anonyme) 348 253
114) Past simple (video) (lucile83) 347 432
115) Past simple or past continuous (lucile83) 340 637
116) While / When (anonyme) 337 634
117) What time is it? (webmaster) 337 329
118) Modals (tinou) 336 191
119) Modal: may/might (lucile83) 333 855
120) Cardinal and ordinal numbers (anonyme) 328 375
121) Possessive adjectives and pronouns (woodyrun) 323 728
122) The superlative (anonyme) 323 631
123) How to talk about the weather (lili73) 320 845
124) Since and for (lucile83) 318 159
125) Flags (webmaster) 317 221
126) Irregular verbs (bridg) 315 571
127) Prepositions - in, on, at (anonyme) 313 829
128) Pronouns (woodyrun) 312 585
129) Tenses (anonyme) 311 280
130) Placement test 3 (webmaster) 310 097
131) Order of adjectives (webmaster) 306 261
132) Could/Couldn't (laure95) 305 550
133) Comparative (anonyme) 304 073
134) Adjectives and prepositions (lucile83) 303 837
135) Agreement Tags (webmaster) 303 753
136) Asking questions (webmaster) 302 803
137) Present perfect OR simple past? (bridg) 298 062
138) Questions in the past tense (lucile83) 297 086
139) Superlative Adjectives (bridg) 295 363
140) Uncountable nouns (webmaster) 295 227
141) Object pronouns (bridg) 294 086
142) Placement test 1 (lucile83) 292 384
143) Present simple (lucile83) 290 351
144) Passive form (anonyme) 289 144
145) Prefer/rather (bridg) 288 964
146) Can/Must/Should (laure95) 288 573
147) Must or Have to? (woodyrun) 286 639
148) Past perfect (lili73) 286 411
149) The/an/nothing (bridg) 284 792
150) To be (anonyme) 283 264
151) Vocabulary: asking and answering (here4u) 280 413
152) Can and can't (laure95) 279 783
153) Modal verbs (bridg) 277 018
154) Some / Any / no... (bridg) 270 024
155) Days of the week (bridg) 269 017
156) So / neither (anonyme) 264 119
157) Past simple (video) (lucile83) 263 413
158) Used to (bridg) 260 191
159) Should / must (anonyme) 259 090
160) Past tense (anonyme) 258 998
161) Vocabulary: on the phone (here4u) 258 683
162) Present continuous (chnawa) 258 606
163) Find out a quantity (webmaster) 258 406
164) Superlative + and adjective (lucile83) 256 818
165) Articles : a / an / the / Ø (anonyme) 255 410
166) Comparative and superlative (anonyme) 254 075
167) Numbers 1/100 (anonyme) 253 239
168) Modal can (video) (lucile83) 252 627
169) Relatives pronouns (who, which, that...) (anonyme) 247 786
170) Vocabulary: at the restaurant (here4u) 245 627
171) Comparatives (anonyme) 245 288
172) A few, a little, few, little (anonyme) 244 810
173) Would rather / would prefer to (anonyme) 244 055
174) Present continuous and the Going to form (anonyme) 242 263
175) Have something done (anonyme) 239 559
176) Should/ have to/ must (anonyme) 239 190
177) The past (webmaster) 237 669
178) Future continuous and future perfect. (felin) 237 361
179) Used to/would (woodyrun) 236 990
180) How to ask a question in English (bridg) 234 917
181) I wish, if only (felin) 233 887
182) Pluperfect (webmaster) 233 617
183) Countable or Uncountable? (webmaster) 232 865
184) Some / any (younes91) 231 733
185) Should / shouldn't (anonyme) 231 059
186) Present simple or continuous (bridg) 230 765
187) Adjectives - ing and ed (felin) 228 600
188) Hypothesis (webmaster) 227 796
189) Auxiliary BE (lucile83) 226 201
190) Articles a/an/the/0 (bridg) 225 994
191) Article The or nothing (anonyme) 225 667
192) Present perfect with Ever - never - (anonyme) 225 269
193) Present continuous OR Present simple? (bridg) 225 144
194) Must or mustn't (laure95) 224 449
195) Simple Preterite OR Preterite (BE+ing) (webmaster) 222 623
196) To / in order to / so as to / so that (irish21) 219 549
197) Present perfect (bridg) 219 214
198) What time is it ? (anonyme) 217 399
199) Comparison (komiks) 216 955
200) Indirect speech (bridg) 215 890
