Works like Visuddhimagga covers 40 types of meditations. I am looking for the original source of these meditations within the Tripitaka. Ideally with complete bibliographical references to the occurrences within the Tripitaka.
The excerpt given below provides some references but in the pages following this one, the meditation subjects are explained and many more references are given. With this in mind, I suggest going to the link provided at the end of the excerpt and read these pages to extract the additional references.
§75 FORTY CONCENTRATION EXERCISES
There are forty concentration exercises (kammatthana) leading to the tranquility of the absorptions. They are:
I. Ten kasina exercises: (1) earth kasina, (2) water kasina, (3) fire kasina, (4) wind kasina, (5) blue kasina, (6) yellow kasina, (7) red kasina, (8) white kasina, (9) light kasina, (10) space kasina. The older suttas replace the light kasina with the consciousness kasina, as at AN 10:29.
II. Ten perceptions of loathsomeness (asubha-sañña): a swollen-up corpse, a bluish discoloured corpse, a festering corpse, a split corpse, a gnawed corpse, a scattered corpse, a dismembered and scattered corpse, a blood-stained corpse, a corpse full of worms, a skeleton. More or less identical with these exercises are the nine cemetery contemplations in MN 10 and DN 22, and the contemplation in AN 4:14, quoted below.
III. Ten contemplations (anussati): (1) on the Buddha, (2) the Doctrine, (3) the Community of Noble Disciples, (4) morality, (5) liberality, (6) heavenly beings, (7) death, (8) body, (9) in-and-out-breathing, (10) peace. While 1-6 are mostly explained in one and the same sutta, (7)—(10) are described each separately in different suttas, e.g. (7) in AN 8:73f. (8) in MN 119 (but not as in MN 10, while in Vism the meditation refers to the thirty-two parts of the body); (9) in MN 118; (10) in AN 9:52-61, 10:26.
IV. Four divine abodes (brahma-vihara): (1) all-em bracing kindness (metta), (2) compassion (karuna), (3) altruistic joy (mudita)), (4) equanimity (upekkha).
V. Four immaterial spheres (arupayatana): (1) sphere of boundless space, (2) sphere of boundless consciousness, (3) sphere of nothingness, (4) sphere of neither-perception-nor-non-perception.
VI. Perception of the loathsomeness of food.
VII. Analysis of the four elements.
Neighbourhood concentration may be reached by III 1-7, 10; VI; and VII.
The first jhana may be reached by II 1-10 and III 8.
The first three jhanas may be reached by IV 1-3.
The four jhanas may be reached by I 1-10 and III 9.
The fourth jhana may be reached by IV 4.
The immaterial attainments may be reached by V 1-4.
The acquired image (uggaha-nimitta) and counter-image (patibhaga-nimitta) will arise only on realizing I 1-10; II 1-10; III 8, 9: hence in twenty-two exercises.
For a full explanation of these forty exercises, see Vism III—XI.
For further details about jhana, etc., see Fund. IV.
-The Buddha's Path of Deliverance, p.75 by Nyanatiloka Thera