The eight rahasyagranthasPeriyavāccān̲piḷḷai aruḷicceyta eṭṭu rahasyakrantaṅkaḷ: Paranta rahasyam, Māṇikkamālai, Sakalapramāṇatātparyam, Rahasyatraya tīpikai, Rahasyatraya vivaraṇam, Nikaman̲appaṭi, Vārttāmālai, Upakāra smruti (1948; Ed. by K. Śrīnivāsayyaṅkār. Tirucci: Srinivasam Press): this edition contains all the available rahasyagranthas by Piḷḷai, perhaps the only one that exists. (Another place where you can download the same edition.)
Piḷḷai Lokācārya
His 18 theological treatises (Aṣṭādaśarahasyaṅkaḷ) are available in this 1889 edition.
His magnum opus, the Śrīvacanabhūṣaṇam(SVB), can be found here; and here, as a simple typed-out (unpublished) text ; and with Maṇavāḷa Māmuṉikaḷ’s Manipravala commentary, it is available here (although it is an unknown edition); and here and here, with PB Annangaracharya’s modern commentary. Can also be downloaded an old edition in the Telugu script here; in the Telugu script, along with his Tattvatrayam, and Mumukṣuppaṭihere; Robert Lester’s English translation here; a Sanskrit rendering of this work, along with Maṇavāḷa Māmuṉikaḷ’s commentary (also translated into Sanskrit) here; the SVB, along with the commentary Mīmāṃsābhāṣyamin the Telugu script here; an English glossary by Gwalior Satyamurthi Iyangar here;
His another equally important work, the Mumukṣuppaṭican be downloaded here; and here in the Telugu script; and here with a modern Tamil explanation; and here with a Tamil rendering of Maṇavāḷa Māmunikaḷ’s commentary.
Aḻakiya Maṇavāḷa Perumāḷ Nāyaṉār
His magnum opus, the Ācāryahṛdayam: text only (although it’s not clear what edition this is), for its commentaries, see here. For a Tamil retelling, see Purushottama Naidu’s useful work (vol. 1 and vol. 2).
Another work by him is the Rahasyavivekam, and here’s a 2006 edition.
Vedānta Deśika
Deśikaprabandham: Tēcikap pirapantam (Uraiyuṭaṉ) (2009 [1944]). Ed. and commented by Śrīrāmatēcikācāryar Svāmi. Ceṉṉai: Ti liṭṭil pḷavar kampeṉi (LIFCO): This edition that contains minor theological works by Deśika, both in Tamil and Manipravalam comes with a neat gloss in modern (but formal) Tamil. Different, older editions (1936, and 1944 and 1967) also exist.
Cillaṟai rahasyaṅkaḷ: Śrīman nikamānta mahātēcikaṉ aruḷiya cillarai rahasyaṅkaḷ (1998; 3 vols. Ed, by Va. Na. śrīrāma Tēcikāccārya Svāmi. Śrīraṅkam: Pauṇṭarīkapuram Śrīmatāṇṭavaṉ Ācramam) – vol 1; vol. 2 (missing; an older edition of the second part can be found here); vol. 3: his other minor theological works, collected under this name.are also important works in Manipravala, as Deśika briefly explains important topics, like the glory of the añjali, surrender, etc.
Abhayapradānasāram: Śrīraṅkācāriyar’s edition (year Citrabhānu), and another place to download it. – this is a treatise that presents the Rāmāyaṇa as the ultimate śaraṇāgatiśāstra. Another edition here.
Rahasyatrayasāram : this is Deśika’s masterpiece which deals in detail with the three chief mantras (inter alia). here is an 1909 edition, or even an 1819 (?) edition that uses the Grantha script as well. You will find here a translation by M. R. Rajagopala Ayyangar (1946) Srimad Rahasyatrayasara of Sri Vedantadesika. Kumbakonam: Agnihothram Ramanuja Thathachariar).
His Añjalivaibhavam explains the greatness of joining hands in prayer. Here’s an edition of the work.
An English rendering of select passages from the Pādukāsahasram, Yādavābhyudaya and Rahasyatrayasāram.
His Hastigirimāhātmyam: in the Telugu script here;
This edition in the Telugu script, called Śrīvedānta Deśika Granthamālā, has many of his works (vol. 2); and this one contains his stotras.
Maṇavāḷa Māmuṉikaḷ
For his commentary on Piḷḷai Lokācārya’s Śrivacanabhūṣaṇam, see above. For its Tamil rendering by Purushottama Naidu, see here (another place to download that is here).
For his commentary on Aruḷāḷa Perumāḷ Emperumāṉār’s Jñānasāram-Prameyasāram, see here; a more recent edition of that work is here.
Yāmunācārya’sPrameyaratnam.This is a short treatise by a disciple of Vādikesari Aḻakiya Maṇavāḷa Jīyar, not by Yāmuna who was Nāthamuni’s grandson. This work explains the following: vaiṣṇavatva, ācāryavaibhava, upāyaviśeṣa and upeyayāthātmya.
this is an edition with the Ārtiprabandham, Parakālanallāṉ Rahasyam, and Tattvatrayam.
You can download here an influential work called Vilakṣaṇamokṣādhikārinirṇayam by Eṟumpiyappā, one of Māmunikaḷ’s disciples (along with Krishnamachariar’s simple Tamil gloss); and another gloss of a similar nature by Araṅkarājan. An older edition can be found here.
These words (Virodhiparigāraṅkaḷ) are attributed to Rāmānuja, who is said to have spoken them to Vaṅkīpurattu Nampi.