\begin{align*}
x &= 2\cos t, \\
y &= 2\sin t, \\
z &= t/3,
\end{align*}
$0\le t\le 4\pi$
\begin{align*}
x &= t, \\
y &= t^3, \\
z &= t^2,
\end{align*}
$-2\le t\le 2$
\begin{align*}
x &= (2 + \sin(10t))\cos t, \\
y &= (2 + \sin(10t))\sin t, \\
z &= \cos(10t),
\end{align*}
$0\le t\le 2\pi$
\begin{align*}
x &= \tfrac{3}{2}(1+\cos t), \\
y &= \tfrac{3}{2}\sin t, \\
z &= 3\sin\left(\tfrac{t}{2}\right),
\end{align*}
$0\le t\le 4\pi$
\begin{align*}
x &= (1.04)^t \cos t, \\
y &= (1.04)^t \sin t, \\
z &= (1.04)^t,
\end{align*}
$0\le t\le 10\pi$
\begin{align*}
x &= 3\sin\left(\tfrac{7}{4}t\right)\cos(t), \\
y &= 3\sin\left(\tfrac{7}{4}t\right)\sin(t), \\
z &= 3\cos\left(\tfrac{7}{4}t\right),
\end{align*}
$0\le t\le 8\pi$