I don't know if there even are 100 anthology series but I do know there have been quite a few over the years. Why not give it a try as I'm a fan of these and I might even learn of a few I forgot or never knew about.
I'll start it with the obvious:
1)
The Twilight Zone (1959-1964): perhaps the greatest anthology series of them all with superb writing, great acting and unforgettable twists and turns, exploring those places perhaps inside us all but rarely explored.
List so far...
1) The Twilight Zone (1959-1964)
2) The Outer Limits (1963-1965)
3) Thriller (w/Boris Karloff) (1960-1962)
4) Rod Serling's Night Gallery (1969-1973)
5) Science Fiction Theater (1955-1957)
6) Tales of the Unexpected (1979-1988)
7) Alfred Hitchcock Presents (1955-1962)/Alfred Hitchcock Hour (1962-1965)
8) Tales From the Darkside (1983-1988)
9) Love, American Style (1969-1974)
10) Darkroom (1981-1982)
11) Tales From the Crypt (1989-1996)
12) Monsters (1988-1990)
13) Walt Disney's The Wonderful World of Color/The Wonderful World of Disney (1954-1990)
14) The Ray Bradbury Theater (1985-1992)
15) Amazing Stories (1985-1987)
16) Night Visions (2001)
17) Tales of Tomorrow (1951-1953)
18) One Step Beyond (1959-1961)
19) Lights Out (1946-1952)
20) The Hitchhiker (1983-1991)
21) Suspense (1949-1954)
22) Four Star Playhouse (1952-1956)
23) The Twilight Zone (1985-1989)
24) The Outer Limits (1995-2002)
25) The Star and the Story (1955-1956)
26) Alfred Hitchcock Presents (1985-1989)
27) Playhouse 90 (1956-1961)
28) Hammer House of Horror (1980)
29) Out of This World (1962)
30) Out of the Unknown (1965-1971)
31) Kurt Vonnegut's Monkey House (1991)
32) 'Way Out (1961)
33) Masters of Horror (2005-2007)
34) Masters of Science Fiction (2007)
35) Freddy's Nightmares: A Nightmare on Elm Street: The Series (1988-1990)
36) Fear Itself (2008)
37) Ghost Story (AKA: Circle of Fear) (1972-1973)
38) Hammer House of Mystery and Suspense (AKA: Fox Mystery Theater) (1984-1986)
39) Spine Chillers (2003)
40) Dr. Terrible's House of Horribles (2001)
41) Faerie Tale Theatre (AKA: Shelley Duvall's Faerie Tale Theatre) (1982-1987)
42) Perversions of Science (1997)
43) The Veil (1958)
44) Zane Grey Theater (1956-1961)
45) Death Valley Days (1952-1975)
46) Family Theatre (AKA: Father Peyton's Family Theatre) (1949-1958)
47) Telephone Time (1956-1958)
48) Aesop's Fable (1971)
49) Masterpiece Theatre (1971-Present)
50) Masterpiece Mystery (AKA: Mystery!) (1980-Present)
51) The Twilight Zone (2002-2003)
52) Calvacade of America (AKA: DuPont Calvacade Theater/DuPont Theatre) (1952-1957)
53) The United States Steel Hour (1953-1963)
54) The Pepsi-Cola Playhouse (1953-1955)
55) Armstrong Circle Theater (1952-1957)
56) CBS Storybreak (1985)
57) Hallmark Hall of Fame (1951-2011)
58) Goosebumps (1995-1998)
59) Actors Studio (1948-1950)
60) Westinghouse Studio One (1948-1958)
61) Tales From the Cryptkeeper (1993-1994, 1997)
62) General Electric Theater (1953-1962)
63) 13 Demon Street (1959-1960)
64) Schlitz Playhouse of Stars (1951-1959)
65) Lux Video Theatre (1950-1959)
66) The ABC Afternoon Special (1972-1997)
67) Nightmares and Dreamscapes: From the Stories of Stephen King (2006)
68) The Canterbury Tales (2003)
69) Journey to the Unknown (1968-1969)
70) Stars Over Hollywood (1950-1951)
71) The 20th Century Fox Hour (1955-1957)
72) The Revlon Mirror Theater (1953)
73) The DuPont Show with June Allyson/The June Allyson Show (1959-1961)
74) Fireside Theater/Jane Wyman Presents (1949-1958)
75) Letter To Loretta/The Loretta Young Show (1953-1961)
76) Robert Montgomery Presents/Lucky Strike Theater (1950-1957)
77) A Twist in the Tale (1998)
78) Philco Television Playhouse (1948-1955)
79) Chrysler Shower of Stars (1954-1958)
80) Television Playhouse (1947-1948)
81) DuMont Royal Theater (1951-1952)
82) NET Playhouse (1966-1974)
83) CBS Schoolbreak Special/CBS Afternoon Playhouse (1979-1996)
84) Theatre 625 (1964-1968)
85) Murder in Mind (2001-2003)
86) Mystery and Imagination (1966-1970)
87) Douglas Fairbanks Jr. Presents (1953-1957)
88) The Chevrolet Tele-Theatre (1948-1950)
89) Ford Star Jubilee (1955-1956)
90) Once Upon a Classic (1976-1980)
91) Play For Today (1970-1984)
92) The Big Story (1949-1958)
93) Appointment with Adventure (1955-1956)
94) Play of the Week (1959-1961)
95) ITV Play of the Week (1955-1968)
96) Armchair Theatre (1956-1974)
97) Festival of Family Classics (1972-1976)
98) The Goodyear Television Playhouse/Goodyear Mystery Theatre (1951-1957)
99) Kraft Television Theatre (1947-1958)
100) Teatro Popular Caracol (1972-78)