This project is based on US-QWERTY and is forked from the EurKEY Keyboard Layout.
In UltimateKEYS, all keys are exactly organized as US-QWERTY. When AltGr or AltGr+Shift is pressed in combination with another key, other diacritics and symbols are accessible and some keys become dead keys.
In that way, it is - somehow - similar to the layout "United States-International" (on Windows), although this project moves all dead key combinations to the modifiers AltGr and AltGr+Shift. That way, this project solves the most typical caveats, among which the quotes (' and ") can be used as usual (without pressing the spacebar afterwards), while the acute accent (´) and diaeresis (¨) are found under Alt and Alt+Shift respectively.

a -> à A -> À ä (AltGr + a) -> ą Ä (AltGr + A) -> Ą c -> ç C -> Ç d -> ḑ D -> Ḑ e -> è E -> È ë (AltGr + e) -> ę Ë (AltGr + E) -> Ę f -> ♀ g -> ģ G -> Ģ h -> ḩ H -> Ḩ i -> ì I -> Ì ï (AltGr + i) -> į Ï (AltGr + I) -> Į k -> ķ K -> Ķ l -> ļ L -> Ļ m -> ♂ n -> ņ N -> Ņ ñ (AltGr + n) -> ǹ Ñ (AltGr + N) -> Ǹ o -> ò O -> Ò ö (AltGr + o) -> ǫ Ö (AltGr + O) -> Ǫ r -> ŗ R -> Ŗ s -> ş S -> Ş t -> ţ T -> Ţ u -> ù U -> Ù ü (AltGr + u) -> ų Ü (AltGr + U) -> Ų w -> ẁ W -> Ẁ y -> ỳ Y -> Ỳ , (comma) -> ¸ (cedilla) . (dot) -> ˛ (ogonek) (space) -> ` (grave accent)

a -> ã A -> Ã e -> ẽ E -> Ẽ i -> ĩ I -> Ĩ n -> ñ N -> Ñ o -> õ O -> Õ s -> ș S -> Ș t -> ț T -> Ț u -> ũ U -> Ũ v -> ṽ V -> Ṽ y -> ỹ Y -> Ỹ (space) -> ~ (tilde)

a -> â A -> Â c -> ĉ C -> Ĉ e -> ê E -> Ê g -> ĝ G -> Ĝ h -> ĥ H -> Ĥ i -> î I -> Î j -> ĵ J -> Ĵ o -> ô O -> Ô s -> ŝ S -> Ŝ u -> û U -> Û w -> ŵ W -> Ŵ y -> ŷ Y -> Ŷ z -> ẑ Z -> Ẑ (space) -> ^ (circumflex accent)

a -> ă A -> Ă ä (AltGr + a) -> ǎ Ä (AltGr + A) -> Ǎ c -> č C -> Č d -> ď D -> Ď e -> ĕ E -> Ĕ ë (AltGr + e) -> ě Ë (AltGr + E) -> Ě g -> ğ G -> Ğ é (AltGr + g) -> ǧ É (AltGr + G) -> Ǧ h -> ȟ H -> Ȟ i -> ĭ I -> Ĭ ï (AltGr + i) -> ǐ Ï (AltGr + I) -> Ǐ j -> ǰ k -> ǩ K -> Ǩ l -> ľ L -> Ľ n -> ň N -> Ň o -> ŏ O -> Ŏ ö (AltGr + o) -> ǒ Ö (AltGr + O) -> Ǒ r -> ř R -> Ř s -> š S -> Š t -> ť T -> Ť u -> ŭ U -> Ŭ ü (AltGr + u) -> ǔ Ü (AltGr + U) -> Ǔ z -> ž Z -> Ž 3 (number 3) -> ʒ # (Shift + 3) -> Ʒ ³ (AltGr + 3) -> ǯ º (AltGr + Shift + 3) -> Ǯ . (dot) -> ˘ (breve) (space) -> ˇ (caron)

a -> å A -> Å ä (AltGr + a) -> ȧ Ä (AltGr + A) -> Ȧ b -> ḃ B -> Ḃ c -> ċ C -> Ċ d -> ḋ D -> Ḋ e -> ė E -> Ė ë (AltGr + e) -> ȩ Ë (AltGr + E) -> Ȩ f -> ḟ F -> Ḟ g -> ġ G -> Ġ h -> ḣ H -> Ḣ i -> ı I -> İ m -> ṁ M -> Ṁ n -> ṅ N -> Ṅ o -> ȯ O -> Ȯ p -> ṗ P -> Ṗ r -> ṙ R -> Ṙ s -> ṡ S -> Ṡ t -> ṫ T -> Ṫ u -> ů U -> Ů w -> ẘ å (AltGr + w) -> ẇ Å (AltGr + W) -> Ẇ x -> ẋ X -> Ẋ y -> ẙ ÿ (AltGr + y) -> ẏ Ÿ (AltGr + Y) -> Ẏ z -> ż Z -> Ż 1 -> (en space) 2 -> (em space) 3 -> (three-per-em space) 4 -> (four-per-em space) 5 -> (six-per-em space) 6 -> (punctuation space) 7 -> (en quad) 8 -> (em quad) 9 -> (figure space, same length as a digit) 0 -> (zero width space) . (dot) -> ˙ (dot above) (space) -> ˚ (ring above)

a -> ā A -> Ā æ -> ǣ Æ -> Ǣ b -> ƀ B -> Ƀ d -> đ D -> Đ e -> ē E -> Ē g -> ḡ G -> Ḡ h -> ħ H -> Ħ i -> ī I -> Ī l -> ł L -> Ł ø (AltGr + l) -> ḻ Ø (AltGr + L) -> Ḻ o -> ō O -> Ō t -> ŧ T -> Ŧ u -> ū U -> Ū y -> ȳ Y -> Ȳ 1 -> ‐ (hyphen) 2 -> – (en dash) 3 -> — (em dash) 4 -> ― (horizontal bar) 5 -> ‑ (non-breaking hyphen) 9 -> ‒ (figure dash, same length as a digit) 0 -> (soft hyphen) (space) -> ¯ (macron)
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q -> ¶ (pilcrow sign) s -> § (section sign) c -> © p -> ℗ r -> ® t -> ™ T -> ℠ 1 -> № 2 -> ½ 3 -> ⅓ 4 -> ¼ 5 -> ⅔ 6 -> ¾ 7 -> ⅛ 8 -> ⅜ 9 -> ⅝ 0 -> ⅞ h -> ← j -> ↓ k -> ↑ l -> → u -> ↖ n -> ↙ i -> ↗ m -> ↘ = -> ↔ H -> ⇐ J -> ⇓ K -> ⇑ L -> ⇒ U -> ⇖ N -> ⇙ I -> ⇗ M -> ⇘ + -> ⇔ C -> ¤ (currency sign) ä (AltGr + a) -> ₳ (austral sign) í (AltGr + b) -> ₿ (bitcoin sign) Ç (AltGr + C) -> ₢ (cruzeiro sign) ð (AltGr + d) -> ₫ (dong sign) Ð (AltGr + D) -> ₯ (drachma sign) è (AltGr + f) -> ₣ (French franc sign) é (AltGr + g) -> ₲ (guarani sign) ù (AltGr + h) -> ₴ (hryvnia sign) † (AltGr + k) -> ₭ (kip sign) ø (AltGr + l) -> ₺ (Turkish lira sign) Ø (AltGr + L) -> ₤ (lira sign) ó (AltGr + .) -> ₾ (Georgian lari sign) ò (AltGr + ,) -> ₼ (Azerbaijani manat) ñ (AltGr + n) -> ₦ (naira sign) œ (AltGr + p) -> ₱ (peso sign) ý (AltGr + r) -> ₽ (Russian ruble sign) Ý (AltGr + R) -> ₹ (Indian rupee sign) ß (AltGr + s) -> ₪ (new sheqel sign) þ (AltGr + t) -> ₸ (tenge sign) Þ (AltGr + T) -> ₮ (tugrik sign) å (AltGr + w) -> ₩ (won sign) a -> ⅍ (Aktieselskab) d -> · (middle dot) e -> ℮ (estimated symbol) E -> … (horizontal ellipsis) o -> ℓ (script small l) O -> Ω (ohm sign) y -> ✓ (check mark) x -> ✗ (ballot x) ç (AltGr + c) -> ℅ (care of) - (hyphen-minus) -> ⁃ (hyphen bullet) . (dot) -> • (bullet) | -> ⁞ (vertical four dots) (space) -> ©

a -> á A -> Á b -> ɓ B -> Ɓ c -> ć C -> Ć ç -> ḉ Ç -> Ḉ e -> é E -> É i -> í I -> Í g -> ǵ G -> Ǵ j -> ij J -> IJ k -> ḱ K -> Ḱ l -> ĺ L -> Ĺ m -> ḿ M -> Ḿ n -> ń N -> Ń o -> ó O -> Ó ö (AltGr + o) -> ő Ö (AltGr + O) -> Ő p -> ṕ P -> Ṕ r -> ŕ R -> Ŕ s -> ś S -> Ś u -> ú U -> Ú ü (AltGr + u) -> ű Ü (AltGr + U) -> Ű w -> ẃ W -> Ẃ y -> ý Y -> Ý z -> ź Z -> Ź æ -> ǽ Æ -> Ǽ ø -> ǿ Ø -> Ǿ (space) -> ´ (acute accent)

a -> ä A -> Ä e -> ë E -> Ë h -> ḧ H -> Ḧ i -> ï I -> Ï o -> ö O -> Ö t -> ẗ u -> ü U -> Ü w -> ẅ W -> Ẅ x -> ẍ X -> Ẍ y -> ÿ Y -> Ÿ (space) -> ¨ (diaeresis)

a -> α (Greek small letter Alpha)
A -> Α (Greek capital letter Alpha)
b -> β (Greek small letter Beta)
B -> Β (Greek capital letter Beta)
v -> β (Greek small letter Beta)
V -> Β (Greek capital letter Beta)
g -> γ (Greek small letter Gamma)
G -> Γ (Greek capital letter Gamma)
d -> δ (Greek small letter Delta)
D -> Δ (Greek capital letter Delta)
e -> ε (Greek small letter Epsilon)
E -> Ε (Greek capital letter Epsilon)
z -> ζ (Greek small letter Zeta)
Z -> Ζ (Greek capital letter Zeta)
i -> η (Greek small letter Eta)
I -> Η (Greek capital letter Eta)
h -> θ (Greek small letter Theta)
H -> Θ (Greek capital letter Theta)
j -> ι (Greek small letter Iota)
J -> Ι (Greek capital letter Iota)
k -> κ (Greek small letter Kappa)
K -> Κ (Greek capital letter Kappa)
l -> λ (Greek small letter Lambda)
L -> Λ (Greek capital letter Lambda)
m -> µ (micro sign)
M -> Μ (Greek capital letter Mu)
, -> μ (Greek small letter Mu)
< -> Μ (Greek capital letter Mu)
n -> ν (Greek small letter Nu)
N -> Ν (Greek capital letter Nu)
x -> ξ (Greek small letter Xi)
X -> Ξ (Greek capital letter Xi)
o -> ο (Greek small letter Omikron)
O -> Ο (Greek capital letter Omikron)
p -> π (Greek small letter Pi)
P -> Π (Greek capital letter Pi)
r -> ρ (Greek small letter Rho)
R -> Ρ (Greek capital letter Rho)
s -> σ (Greek small letter Sigma)
S -> Σ (Greek capital letter Sigma)
. -> ς (Greek small letter Sigma, in word-final position)
> -> Σ (Greek capital letter Sigma)
t -> τ (Greek small letter Tau)
T -> Τ (Greek capital letter Tau)
y -> υ (Greek small letter Upsilon)
Y -> Υ (Greek capital letter Upsilon)
f -> φ (Greek small letter Phi)
F -> Φ (Greek capital letter Phi)
c -> χ (Greek small letter Chi)
C -> Χ (Greek capital letter Chi)
w -> ψ (Greek small letter Psi)
W -> Ψ (Greek capital letter Psi)
q -> ω (Greek small letter Omega)
Q -> Ω (Greek capital letter Omega)
u -> ω (Greek small letter Omega)
U -> Ω (Greek capital letter Omega)
1 -> ¹ (superscript)
2 -> ²
3 -> ³
4 -> ⁴
5 -> ⁵
6 -> ⁶
7 -> ⁷
8 -> ⁸
9 -> ⁹
0 -> ⁰
- -> ⁻
= -> ⁼
+ -> ⁺
[ -> ⁽
] -> ⁾
! (Shift + 1) -> ₁ (subscript)
@ (Shift + 2) -> ₂
# (Shift + 3) -> ₃
$ (Shift + 4) -> ₄
% (Shift + 5) -> ₅
^ (Shift + 6) -> ₆
& (Shift + 7) -> ₇
* (Shift + 8) -> ₈
( (Shift + 9) -> ₉
) (Shift + 0) -> ₀
; -> ₋
' -> ₌
" -> ₊
{ (Shift + [) -> ₍
} (Shift + ]) -> ₎
(space) -> µ (micro sign)

! -> ≠ ~ -> ≈ = -> ≝ > -> ≥ < -> ≤ - -> ± i -> ∞ n -> ⁿ r -> √ 3 -> ∛ 4 -> ∜ % -> ‰ f -> ƒ S -> ∫ ' -> ′ " -> ″ p -> ∂ d -> Δ D -> ∇ + -> ⊕ * -> ⊗ ^ -> ℘ s -> ∩ u -> ∪ U -> ∖ O -> ∅ g -> ⊂ G -> ⊃ h -> ⊄ H -> ⊅ b -> ⊆ B -> ⊇ m -> ∈ M -> ∉ k -> ∋ K -> ∌ A -> ∀ E -> ∃ X -> ∄ & -> ∧ | -> ∨ c -> ∝ . -> ⋅ o -> ∘ : -> ∴ ; -> ∵ z -> ↯ F -> ∎ R -> ℝ C -> ℂ N -> ℕ P -> ℙ Q -> ℚ Z -> ℤ 9 -> ∟ 8 -> ∠ 7 -> ∡ l -> ∥ L -> ∦ ß (AltGr + s) -> ∑ (space) -> √