Andron Mega is a Venetian Roman face designed to serve scientific publishing, in the fields of humanities and linguistics in particular.
By now Andron Mega Regular contains about 5500 glyphs, it comprises these writing systems:
– Latin
– Cyrillic
– Greek
– Coptic
– Gothic
– Runic
– Ogham
– Old Italic

Exhaustive Unicode support is given for Latin, Greek and Cyrillic. Additionally, Andron Mega provides complete Unicode support for Phonetics and Hundreds of ligatures, fractions, numerals, abbreviations, currency signs, symbols and many other typographical fancies.
Candidates for an upcoming extension of Andron are most likely Hebrew, Armenian and Georgian; perhaps Arabic.

More Roman fonts of the kind are to be find at the MUFI site.

One of them has been upgraded recently: Alphabetum boasts with about 6300 glyphs and many writing systems.

I second Andron Mega. It is a wonderful font, with visual elements that compose a strong identity through all scripts supported.

Another source is Rosetta foundry. Their fonts are also high quality products with multiple script support –although not so wide as Andron.

Alphabetum and the SIL fonts (Doulos, Gentium, Charis) also covers many scripts, but you don't get the same level of visual identity. Another source is Unifont.org: the fonts available also covers many scripts (but again, without high quality design).

Better-than-nothing dept.: The "FSF Free Fonts" are Times/Helvetica/Courier clones with a pretty wide coverage.

Huronia Pro, in development, supports Latin, IPA, Greek (including Polytonic), Canadian Syllabics, and Cherokee.

Sylfaen originally was developed to include Latin, IPA, Cyrillic, Greek, Armenian, Georgian, and Ethiopian, although the released version only includes a subset of these.

Ladoga supports Latin, Cyrillic (including historical), Greek (including Polytonic), and Hebrew; an Armenian component was also developed, although I don't see it in the released version.

In MyFonts, this search shows all text fonts with support for extended Latin, Cyrillic and Greek. I also did the same search also including Hebrew and phonetic alphabets. Another useful search takes all so-called superfamilies, usually with a good language support.

I suppose their search tool has some bugs as there are no results for Indic scripts, although I'm pretty sure MyFonts offers fonts with this option.

Fedra has very wide coverage, including a Hindi and Arabic and Armenian versions.

I'm pretty sure Microsoft system fonts like Arial beat everybody for completeness.

Arial Unicode MS, as Satya said, is basically different typefaces thrown together. Andron Mega, Fedra, and the typefaces I mentioned are multi-script families where the different components were designed to go together.

If you're just looking for fonts that support multiple writing systems, a professional Japanese font may reasonably include hiragana, katakana, kanji, Latin, Greek, and Cyrillic, but the latter three will usually be existing designs chosen to match the specifically Japanese scripts. I know Korean fonts that cover all those writing systems and of course the Korean alphabet, but the same point applies. It is rare to see sizeable multi-script families where each component is designed from scratch to harmonize with one another, not just taken from an existing catalogue. I believe this is why Satya is asking this.

Lots of popular designs like Gill Sans, Meta, Palatino, and Farnham that were not necessarily created to be multi-script families are later adapted to different scripts like Greek, Thai, and Arabic due to client demand.

It’s a monstrous perspective but: ONE decent font containing EVERYTHING in a harmonized fashion – this is the target. I doubt if I happen to see this in my lifetime. Would have to be a very special collaboration.

alright, everything but Chinese ;-)

Oops, I didn't read the original post properly. I think the reality of it is that generally speaking the most common demand is for a latin and a particular non-latin script to go together. Then there are countries where one other script is also common. But more than three in harmony, particularly with very different historical roots? Is there any need for that?

I would assume the need would come from a business which operates in several different companies but wants to maintain a universal similarity among the type.

Are there any examples of typefaces in which the Latin characters are designed after the Arabic, Cyrillic, Armenian glyphs? I would guess with most commonly used typefaces (at least in Europe and North America), the Latin is created and the rest is stylized to look similar. I'd be curious to see the results.

Of course, multi-scripts fonts have a very specific market.
I see a number of scenarios where more than two scripts may be needed:
– Transnational corporations operating in various countries;
– University departments focused on History, Languages and multi-cultural issues;
– Works about Linguistics, History, Anthropology and similar areas;
– Reference books, as dictionaries and encyclopæedias;
– Material produced by international organisations (UN, FAO, WIPO, etc.);
– Software with wide language support;
– Turistic material.

Is there any need for that?

Igor Freiberger has made some good points already for that. Additionally comes to mind:

– the six main languages of the UN are Arabic, Chinese, English, French, Russian and Spanish. There you have 4 writing systems at once.

– In Israel Hebrew, Arabic and Latin are in everyday use, not to forget Russian – 3 or 4 writing systems at once.

– The major scripts of India count about a dozen or more.

– In classical studies there is very often to deal with Hebrew, Greek and Latin on one page, even in the same sentence. Depending on the subject and period dealt with one is likely to additionally encounter Arabic, Phoenician, Syriac, Etruscan, Old Egyptian (3 systems only for that!), Linear A or B, Coptic, Ethiopic, Gothic, Glagolitic, Armenian, Georgian, Runic, … You can establish that situation for any region other than the Euro-Mediterranean: America, Asia, Africa.

– The literal history of Azerbaidzhan comprises Arabic, Cyrillic and Latin. I’m curious how a written history of the land’s literal heritage may look like.

– In user instructions for any technical device you often find the explanations in 20 or more languages, which means: Latin, Cyrillic, Greek, Arabic, Hebrew, Korean, Japanese, Chinese, …

These are only few examples which come to mind instantly. In the age of ”globalization” the multiskriptive situation will rather increase than decline. Beyond the target of 3 or 4 scripts to be adjusted.

...the SIL fonts (Doulos, Gentium, Charis) also covers many scripts, but you don't get the same level of visual identity

Actually, these fonts (esp. Gentium) have been designed with a great deal of visual unity between the scripts (Latin/Cyrillic + Greek in Gentium).

There are a lot of different aspects to visual unity - harmonized sizing (which doesn't mean the same dimensions), perceived weight, consistent level of contrast, curve and terminal styling, etc. So while it's easy to unity Latin & Cyrillic, it's more difficult to add a Hebrew or Arabic to the mix, but it can be done very well.

It’s a monstrous perspective but: ONE decent font containing EVERYTHING in a harmonized fashion – this is the target.

I used to think that, but in the last decade I've completely changed my mind. Browsers and devices these days are quite capable of using fonts specified for specific character ranges. Super Mega Pan Script fonts that try to serve many different scripts equally well are difficult to maintain, take huge resources, and are always a compromise. For example, you can't really do a good job in setting hinting control values or alignment zones when you have a dozen scripts.

It would be much better to instead have an interrelated 'clan' of fonts where any one family only tries to serve scripts that are really visually related. Then multiple families could be used together (international documents, brand packaging...) with both fidelity to the script conventions and harmony to the 'clan'.

Sorry, Victor. I checked Gentium now with more attention and it is really a great work. Probably my opinion was incorrectly based on the natural differences between the scripts.